THE ASESSMENTS OF ALL SPECIES CAUGHT BOTH TARGET AND BYCATCH IN THE ECIFF
Threatened species that the ECIFF may interact with:
Carcharias taurus – Grey Nurse Shark (east coast population) – Critically endangered Glyphis sp. A – Speartooth Shark – Critically endangered
Caretta caretta – Loggerhead Turtle – Endangered
Lepidochelys olivacea – Pacific Ridley, Olive Ridley – Endangered
Chelonia mydas – Green Turtle – Vulnerable
Dermochelys coriacea – Leathery Turtle, Leatherback Turtle, Luth – Vulnerable Eretmochelys imbricata – Hawksbill Turtle – Vulnerable
Natator depressus – Flatback Turtle – Vulnerable
Megaptera novaeangliae – Humpback Whale – Vulnerable
Carcharodon carcharias –White Shark – Vulnerable
Pristis microdon – Freshwater Sawfish – Vulnerable
Pristis zijsron – Green Sawfish
Dindagubba, Narrowsnout Sawfish – Vulnerable
Rhincodon typus – Whale Shark – Vulnerable
DOMINATED CATCH: 6 species, of these 3 are listed as near threatened, one is listed as endangered.
Carcharhinus tilstoni (Australian Blacktip Shark)
Status: Least Concern
What information is available on species mix suggests that while the majority of the targeted catch is based on relatively productive species (milk sharks, spot-tail and Australian blacktip) a number of much less productive species are also taken. An added complication is that catches of Australian blacktips (Carcharhinus tilstoni) appear to be mixed with the common blacktip (C. limbatus); these two species are very difficult to tell apart. However common blacktips are much less productive and their abundance in the catch would increase in southern areas of the fishery.
The scalloped hammerhead shark (Sphyrna lewini)
Status: Endangered
Pups occupy shallow coastal nursery grounds, often heavily exploited by inshore fisheries, and then migrate offshore as they mature.
Male Scalloped Hammerheads reach sexual maturity at an age of about 10 years. Females of the species reach sexual maturity an age of about 15 or 16 years.
The scalloped hammerhead (Sphyrna lewini) was a significant part of the Queensland shark catch (18 per cent of commercial catch in the ECIFF during observer trips, Attachment 3), and is one of the species that risk assessments by QDPI&F and CSIRO have identified as having a high sustainability risk.
these proportions equate to estimated catches of 143 tonnes per year for scalloped hammerhead.
Status: Near Threatened
It is known now that its reproductive level is too low, and was exploited in previous fisheries where the population catch was reduced to only a quarter of previous years.
The spot-tail shark (C. sorrah) was a relatively large contributors to the catch numbers on observer trips.
(June 2007 ) To date, no stock assessments have been completed for sharks and rays taken in the ECIFF. Work is underway on stock assessments for the two principle target species (Australian blacktip shark Carcharinus tilstoni and Spot-tail shark C. sorrah). The most concerning and recent results from research has reported that populations of white tip reef sharks and grey reef sharks have collapsed on reefs in the northern and central Great Barrier Reef27 (both of these species are caught by the ECIFF, see Attachment 3). The study notes the need to review the conservation status of these species28.
The lack of stock assessments and population estimates for sharks and rays caught in the ECIFF mean that population declines are unlikely to be detected for most species. In light of this, risk assessments are being used to infer the ecological sustainability of species and classify sharks and rays according to their relative vulnerability to overfishing.
The white-cheek shark Carcharhinus dussumieri, Widemouth Blackspot Shark
This small species of shark is particularly susceptible to inshore fisheries, being caught commonly as bycatch in commercial trawling, artisanal fishing, hook-and-line fishing and gillnetting throughout its range. It has a low reproductive capacity, with a normal litter size of two, making it vulnerable to over-exploitation. It also enters the shark fin trade.
In Australia this species is classified as Least Concern, as regional fishing pressure appears sustainable. However, continued fishing pressures throughout its range will result in further declines and populations require monitoring.
The life history characteristics of this species, together with its small size, make local populations particularly sensitive to fishing-induced declines.
in Northern Australia appears fairly robust, there is evidence of severe depletions, including local extirpations, of this species in coastal waters throughout parts of its range in Asia (only a matter of time until this occours in Australia) There are no data on the age at maturity or longevity of this species.
milk shark (Rhizoprionodon acutus)
Status: Least Concern
Status: Near Threatened
The Grey Reef Shark (Carcharhinus amblyrhynchos) is a widespread, social species that formerly was common in clear, tropical, coastal waters and oceanic atolls. Its restricted habitat, site fidelity, inshore distribution, small litter size, and relatively late age at maturity, along with increasing fishing pressure suggests that this species may be under threat. Although caught in tropical multi-species fisheries, it has considerably greater value in dive tourism if protected. With time and additional data, this Near Threatened assessment may need to be revised.
This shark shows high site fidelity and some local populations have been severely depleted by modest fishing pressure,
Because Grey Reef Sharks are found in clear tropical waters over coral reefs, they are ideal for non-consumptive (but much more lucrative) use in the form of tourism diving, as has been shown by Anderson and Ahmed (1993).
BY CATCH IN THE ECIFF (rays & sharks)
Rhinobatus typus Giant shovelnose ray (UNIVERSAL FISH CATALOGUE)
No common names are available for this name combination.
Habitat: No habitat information has been entered yet.
Distribution: Indo-West Pacific.
Not listed on the IUCN red list.
Status: Data Deficient
IUCN Red List of Threatened Species.
Himantura uarnak (Reticulate Whipray)
Status: Vulnerable
Rhinotera neglecta (Rhinoptera neglecta)
Australian Cownose Ray
Status: Data Deficient
Loxodon macrorhinus Sliteye shark (Jordan's Blue Dogshark)
Status: Least Concern
Status: Near Threatened
In Australia listed as least concern: FOR NOW. Its happened and been seen in the past in other countries from exploitation from fisheries, so what’s to stop it from eventually occurring in Australia. Within Australian waters it is only lightly exploited by gillnet and long line fishing.
There are no scientific data on its status, and biological data are incomplete, but based on anecdotal accounts and market surveys the population is assumed to have declined and is assessed as Near Threatened. In the future it may reach a level that would warrant a Vulnerable listing.
There are no conservation measures for this species.
Approximately 25 species were least likely to be sustainable in the ECIFF. Of these, Eleven species had a susceptibility rank above 2.33 and a recovery rank between 1.66 and 2.33 and were also least likely to be sustainable. These species include Eusphyra blochii.
Species of sharks and rays identified by the Scientific Advisory Group of the Inshore Finfish Management Advisory Committee in February 2007 as high or moderate risk: Eusphyrna blochii: high risk!
Orectolbus ornatus wobbegong
Near threatned.
Assessment is complicated by taxonomic uncertainties based on the identification of the PNG specimen. This species should at present be considered as an Australian endemic (L.J.V. Compagno, pers. comm.).
Age and growth of O. ornatus was attempted but could not be verified or validated (Huveneers 2007).
Commercial fishing is probably the main cause of the decline of this species in eastern Australia. Furthermore, observed site fidelity is likely to increase wobbegong?s susceptibility to fishing pressure. On an Australia-wide basis, wobbegong sharks are commonly caught in trawls, beach seines, gillnets, lobster pots and traps, by hook-and-line, and also by spearfishing. The flesh is now highly regarded as food, but in the past has generally been of only limited commercial value. Historically, the attractive skin has been used as decorative leather (Last and Stevens 1994). However, it is unknown if this practice is still occurring.
Red List Category & Criteria: Critically Endangered
Australian populations have declined significantly as a result of bycatch in commercial gillnet and trawl fisheries throughout this limited range and this bycatch continues, in commercial and recreational fisheries.
Anoxypristis cuspidata (Knifetooth Sawfish, Narrow Sawfish, Pointed Sawfish)
Critically Endangered
K-selected life history have caused substantial reductions in abundance, the fragmentation of remaining populations and the virtual disappearance of this species from commercial catches in regions where it was once considered fairly common.
Age at maturity, longevity and average generation time are unknown.
The principal threat to all sawfishes is fisheries, both targeted and bycatch, commercial and subsistence.
Bycatch is comprised mainly of fish and elasmobranch species. Elasmobranchs taken as bycatch include and the protected narrow sawfish.
scientific observer program, and lower catch frequencies in the Qld Shark Control Program long-term data series, suggest that the abundance of sawfish is much reduced over their east coast range (N. Gribble, DPI&F, pers. obs., 2004).
Research into sawfish biology, distribution, catchability and survivability after capture is also being undertaken in the GoCIFF as part of the Shark Phase II project (Roelofs 2002). Results from this research will be used in the development of a full ecological risk assessment on the sustainability of a broad range of east coast elasmobranchs interacting with the fishery (N. Gribble, DPI&F, pers. comm., 2004). When available,
findings from the full risk assessment will be considered to ensure that the ECIFF management regime is sustainably managing east coast pristid catches. MEANWHILE…
Pristis pectinata (Wide Sawfish) – (expected to be restricted to the gulf and not found on the east coast)
Status: Critically Endangered
Pristis perotteti (Largetooth Sawfish)
Status: Critically Endangered
Pristis pristis (Common Sawfish)
Status: Critically Endangered
Pristis zijsron (Narrowsnout Sawfish)
Status: Critically Endangered
OTHER SPECIES CATCH AND RETAINED:
Carcharhinus altimus (Bignose Shark)
Status: Data Deficient
Carcharhinus amblyrhynchoides
Red List Category & Criteria: Near Threatened
The Graceful Shark is exploited for its flesh and fins. There is no information available on the impact of fishing on C. amblyrhynchoides stocks.
The Graceful Shark (Carcharhinus amblyrhynchoides) is a little-studied, coastal Indo-West Pacific species that is caught in commercial fisheries, but not as a targeted species. There is no evidence that this species faces a high extinction risk under the IUCN Criteria, but it has been impacted by fishing. Further research is required on its life history to aid in the assessment of this species.
Sawfishes were the least sustainable group with all four species having the highest susceptibility ranks due to the fact that they are captured by prawn and fish trawls, gill nets and long lines**. Other species that were least likely to be sustainable*** were C. amblyrhynchoides, C. amboinensis, C. brevipinna, C. leucas, C. limbatus, Glyphis sp. A, Glyphis sp. C, N. acutidens, S. mokarran, and E. blochii.
Eleven species had a susceptibility rank above 2.33 and a recovery rank between 1.66 and 2.33 and were also least likely to be sustainable. These species include Carcharhinus amblyrhynchoides, C. cautus, C. melanopterus, C. fitzroyensis, Eusphyra blochii and Rhynchobatus australiae.
(Table 2. Summary of the sustainability of species from the risk assessment of target and by- catch fisheries to sharks and rays in Northern Australia published by CSIRO in 2007*)
Carcharhinus amboinensis (Pigeye Shark, Java shark)
Status: Data Deficient
Where fisheries data are available, this species constitutes a very small component of the catch, suggesting that it may not be common.
Given its apparently sporadic distribution and low abundance, this shark may be unable to sustain heavy, localised fishing pressure. In the absence of further information, it is classified globally as Data Deficient. However, data are available from South Africa demonstrating a significant declining trend in catches, hence the Near Threatened assessment for the Southwest Indian Ocean Subpopulation. Given the low incidence of this species in commercial catches, there are no known conservation and management initiatives.
(data deficient because none are being caught to study- already fished out?)
Sawfishes were the least sustainable group with all four species having the highest susceptibility ranks due to the fact that they are captured by prawn and fish trawls, gill nets and long lines**. Other species that were least likely to be sustainable*** were C. amblyrhynchoides, C. amboinensis, C. brevipinna, C. leucas, C. limbatus, Glyphis sp. A, Glyphis sp. C, N. acutidens, S. mokarran, and E. blochii. (Table 2. Summary of the sustainability of species from the risk assessment of target and by- catch fisheries to sharks and rays in Northern Australia published by CSIRO in 2007*)
Carcharhinus brevipinna (Spinner Shark)
Status: Near Threatened
Is frequently captured in recreational and commercial fisheries. It is a species that frequents near shore waters as adults and has inshore nursery areas, making it highly vulnerable to fishing pressure and human-induced habitat alteration.
There are no conservation measures in place for this species.
As with most carcharhinid species, the Spinner Shark meat is sold under the name ?Blacktip Shark? because of wide consumer preference for the product. Probably it is represented in the shark catches in most areas within its range, but owing to confusion with the Blacktip Shark, it is likely that the species is not recorded in landings data. Fins are dried and shipped to the Far East where they are used in shark fin soup. In some areas the hides are likely to be utilized in preparing leather and the livers are used to extract oil.
Sawfishes were the least sustainable group with all four species having the highest susceptibility ranks due to the fact that they are captured by prawn and fish trawls, gill nets and long lines**. Other species that were least likely to be sustainable*** were C. amblyrhynchoides, C. amboinensis, C. brevipinna, C. leucas, C. limbatus, Glyphis sp. A, Glyphis sp. C, N. acutidens, S. mokarran, and E. blochii.
The CSIRO risk assessment of target and by-catch fisheries to sharks and rays in Northern Australia provided fishery-level assessments, including for the ECIFF, plus a cumulative risk assessment for all northern Australian fisheries. Approximately 25 species were described as ‘least likely to be sustainable’ in the ECIFF (see Attachment 3 – Table 2). These species include: C. brevipinna.
Carcharhinus cautus (Nervous Shark)
Status: Data Deficient
Females mature at 5 to 6 years and reach maximum size at 16 years. Litters of 2 to 6 are produced at two-year intervals. Relatively little is known about its population structure and dynamics. It occurs in areas of northern Australia that are targeted by a moderate level of prawn trawling and coastal/estuarine gillnetting. This species is probably taken as a bycatch in both fisheries, but with a greater likelihood of being caught in the inshore gillnet fishery. Discard/release mortality is probably significant but these fisheries are not thought to be detrimental to the Australian population (where this species is assessed as Least Concern). It will also be taken (and presumably not discarded) in shallow coastal gillnet and line fisheries elsewhere in its range, where no data are available.
This species is threatened primarily by inshore gill-net fisheries throughout its range.
Future research should examine the level of bycatch in these fisheries, together with their attendant mortalities. individual sharks caught in nets die quickly of hypoxia. Practical action in the form of net restrictions will be the only effective measure. Research into population sizes and movements of individuals, via tag-release-recapture studies, is required to better understand this species.
East Coast Inshore Finfish Fishery
Approximately 25 species were least likely to be sustainable in the ECIFF (Figure 6.5-7 of Salini et al 2007). Of these, 14 species had susceptibility and recovery ranks above 2.33 and were the least sustainable species in this fishery. These species include C. amboinensis, C. brevipinna, C. leucas, C. limbatus, C. tilstoni, Glyphis sp. A, Negaprion acutidens, Pristis zijsron, P. microdon, S. mokarran. Eleven species had a susceptibility rank above 2.33 and a recovery rank between 1.66 and 2.33 and were also least likely to be sustainable. These species include Carcharhinus amblyrhynchoides, C. cautus, C. melanopterus, C. fitzroyensis, Eusphyra blochii and Rhynchobatus australiae.
Carcharhinus fitzroyensis (Creek Whaler)
Status: Least Concern
Small numbers of this species are caught in northern inshore gill-net fisheries. Juveniles that use embayments as nursery areas are at potential risk of gill-netting, which could depress populations locally. However, the species is relatively fecund and populations should prove resilient.
East Coast Inshore Finfish Fishery
Approximately 25 species were least likely to be sustainable in the ECIFF (Figure 6.5-7 of Salini et al 2007). Of these, 14 species had susceptibility and recovery ranks above 2.33 and were the least sustainable species in this fishery. These species include C. amboinensis, C. brevipinna, C. leucas, C. limbatus, C. tilstoni, Glyphis sp. A, Negaprion acutidens, Pristis zijsron, P. microdon, S. mokarran. Eleven species had a susceptibility rank above 2.33 and a recovery rank between 1.66 and 2.33 and were also least likely to be sustainable. These species include Carcharhinus amblyrhynchoides, C. cautus, C. melanopterus, C. fitzroyensis, Eusphyra blochii and Rhynchobatus australiae.
Carcharhinus leucas (Bull Shark)
Status: Near Threatened
It is caught in fisheries throughout its rang due to its freshwater roaming abilities.
The frequent use of estuarine and freshwater areas by the Bull Shark makes it more susceptible to deleterious human impacts than species of sharks occurring in other coastal or offshore areas.
The CSIRO risk assessment of target and by-catch fisheries to sharks and rays in Northern Australia provided fishery-level assessments, including for the ECIFF, plus a cumulative risk assessment for all northern Australian fisheries. Approximately 25 species were described as ‘least likely to be sustainable’ in the ECIFF, These species include: bull shark C. leucas,
Carcharhinus macloti (Hardnose Shark)
Status: Near Threatened
Although of small size, its life history may not be as productive as that of other small carcharhinids (e.g., Rhizoprionodon spp.), making it more susceptible to fishing pressure. It is assessed as Near Threatened because continuing fishing pressure may reduce the population to a level where it may meet the criteria for Vulnerable.
No species-specific conservation measures are in place.
Carcharhinus melanopterus (Blacktip Reef Shark)
Status: Near Threatened
Due to small litter sizes and long gestation periods, is vulnerable to depletion.
Although this species is used fresh and dry salted for human consumption and for its liver-oil (Last and Stevens 1994) it is considered to be of little commercial importance (Lyle 1987). Data concerning the take of this species in artisanal fisheries is scarce, but due to its inshore, shallow water habitat it is likely to be a target of such activities.
There are currently no conservation or management plans in effect for this species.
Eleven species had a susceptibility rank above 2.33 and a recovery rank between 1.66 and 2.33 and were also least likely to be sustainable. These species include C. melanopterus.
There are a number of chondrichthyan species that are associated almost exclusively with coral reefs, including the whitetip reef shark (Triaenodon obesus), blacktip reef shark (Carcharhinus melanopterus), grey reef shark (Carcharhinus amblyrhynchos) and Caribbean reef shark (Carcharhinus perezi) (Compagno, 1984). These species may be more susceptible to exploitation and changes in habitat quality than species that range broadly amongst habitats because of their high level of habitat association (Wetherbee et al., 1997; Garla et al., 2006a). Reef associated shark species often have complex distributions, however, making the interpretation of data associated with them complex.
Carcharhinus brachyurus (Bronze Whaler)
Status: Near Threatened
This species is slow to reproduce.
Although widespread, regional populations appear to be discrete, and movement of individuals between them is thought infrequent or absent, and it does not appear to be naturally abundant anywhere. Throughout its range, it is known to be exploited by fisheries, but landings are grouped together with other Carcharhinus species, meaning any population declines are likely to go unnoticed, and its coastal nursery areas are potentially vulnerable to development and pollution. This, together with life history characteristics that make it especially vulnerable to overfishing has led to the global assessment of C. brachyurus as Near Threatened.
It is mainly taken as bycatch in gill net and bottom longline fisheries for bony fishes and other sharks. It is also taken by bottom trawl and pelagic longline but only forms a minor component of the catch in these fisheries.
Carcharhinus falciformis: Silky shark
Red List Category & Criteria: Near Threatened
It is vulnerable to a wide variety of pelagic fisheries, and is taken in large numbers, but there are no population estimates and most catches are unreported.
Silky Sharks were found to represent at least 3?4% of the fins auctioned in Hong Kong, the world?s largest shark fin trading center?the 3rd highest after Blue Sharks (Prionace glauca) and Scalloped Hammerhead Sharks (Sphyrna lewini) (Clarke et al. 2006a)?and Hong Kong is thought to make up more than 50% of the global shark fin trade (Clarke et al. 2004, 2006b). Silky Shark fins are valuable to the trade, although they are not one of the highest value fin types (S. Clarke, unpubl. data).
Silky Shark ranks among the three most important sharks in the global shark fin trade, with between half a million and one and a half million Silky Sharks traded annually.
This oceanic and coastal-pelagic shark is circumglobal in tropical waters, where it dominates as a target species or bycatch in certain pelagic fisheries, particularly purse seines on drifting FADs (fish aggregating devices). Population dynamics and structure are poorly known.
Carcharhinus obscurus (Dusky Shark)
Status: Vulnerable
The Dusky Shark (Carcharhinus obscurus) is a large wide-ranging coastal and pelagic warm water species, which is among the slowest-growing, latest-maturing of known sharks, bearing small litters after a long gestation period. Its very low intrinsic rate of increase renders this species among the most vulnerable of vertebrates (including the great whales and sea turtles) to depletion by fisheries.
The fishery for C. obscurus off southwestern Australia developed in the 1940s, but rapidly increased in the late 1970s to produce annual catches of 500?600 t. The fishery uses demersal gillnets (16.5 to 17.8 cm stretched mesh) to target neonates in the nursery area and the selectivity of the nets results in very few individuals over three years of age being captured. The flesh of the young C. obscurus is highly regarded and fetches a good price on local markets. Fins are also sold. Current estimates are that 18?28% of neonates are caught in their first year. An assessment using demographic models indicated that the fishery was sustainable at the then level of catch provided the fishing mortality of animals larger than two metres was less than 4% (Simpfendorfer 1999). However, a more recent assessment (McAuley et al. 2005) found that the stock was less productive than previously thought, and that mortality of older dusky sharks in wetline fisheries outside the target fisheries was leading to a decline in recruitment. This assessment also estimated that the catch per unit effort (CPUE) of Dusky Sharks declined by more than 75% between the early 1970s and 2004, and that the decline was continuing. In 2006 additional management measures were introduced to the fishery (see below), including a maximum size limit for Dusky Shark. These management measures should arrest further declines, but continued monitoring and assessment will be essential to monitor the stock, and the effectiveness of these measures.
All this considered, the species is assessed as Near Threatened throughout Australian waters, close to meeting the criteria for Vulnerable. Continued monitoring and regular reassessment is recommended.
This species is estimated to have undergone population decline in several areas of its range.
The lack of large yolky ova in the ovary of late-term pregnant C. obscurus indicates that there is one year resting period between birth and mating, making the reproductive cycle at least three years long (Musick 1995, Branstetter and Burgess 1996, Romine 2004).
(The dusky whaler, Carcharhinus obscurus (Lesueur, 1818), is a widely distributed large aggressive pelagically feeding species with a typical elasmobranch life history. Off southwestern Australia, regulated mesh size of gillnets ensures the fishery principally captures neonates (age 0) with some juveniles (1–4 years old). Historically fishing mortality on adults has been zero. Simpfendorfer (1999) concluded that, "one possible strategy for the sustainable exploitation of long-lived, late-maturing, slow-growing, slow-reproducing marine species is to target exploitation at the youngest age-classes.")- Gauntlet Fisheries for Elasmobranchs – the Secret of Sustainable Shark Fisheries. (Jeremy D. Prince).
Carcharhinus plumbeus (Sandbar Shark)
Status: Vulnerable
Tagging, age and growth studies show that Sandbar Sharks are long-lived, with low fecundity and are consequently very vulnerable to over-fishing.
Sandbar Sharks are slow-growing K-selected species (Hoff 1990, Sminkey and Musick 1995). Although growth and age at maturity may be accelerated under captive conditions (Wass 1973), wild populations grow very slowly and mature at a relatively late age. The estimated generation and population doubling times of approximately 23 years, indicated a lengthy recovery period for the stock should it be reduced to lower than acceptable levels (McAuley et al. 2005). Regardless, Sandbar Sharks grow slowly and mature late. Longevity is 35-41 years (Musick 2005, McAuley et al. 2006).
It is an important component of shark fisheries in most areas where it occurs and has been severely overfished in the Northwest and Western Central Atlantic, Mediterranean, Southern Brazil and probably the Northeast Pacific. It has declined from fishing off western Australia and is common but not fished in Hawaiian waters (Romine et al. 2006).
Carcharhinus limbatus Black tip shark.
Red List Category & Criteria: Near Threatened
Its meat is well-regarded and its fins are highly marketable.
It frequents inshore waters as adults and has inshore nursery areas, making it highly vulnerable to fishing pressure and human-induced habitat alteration.
In Australia, it represents a minor component of the shark catch in northern Australia (Last and Stevens 1994). Blacktip Shark meat is primarily consumed locally and fins are dried and shipped to the Far East where they are used in preparing shark-fin soup. In some areas the hides are utilised in preparing leather and the livers are used to extract oil.
East Coast Inshore Finfish Fishery
Approximately 25 species were least likely to be sustainable in the ECIFF (Figure 6.5-7 of Salini et al 2007). Of these, 14 species had susceptibility and recovery ranks above 2.33 and were the least sustainable species in this fishery. These species include C. limbatus,
Cumulative risk assessment for all northern Australian fisheries
Sawfishes were the least sustainable group with all four species having the highest susceptibility ranks due to the fact that they are captured by prawn and fish trawls, gill nets and long lines**. Other species that were least likely to be sustainable*** were C. amblyrhynchoides, C. amboinensis, C. brevipinna, C. leucas, C. limbatus.
By weight, the target species of the fishery, C. tilstoni/C. limbatus and C. sorrah, also dominated the catch, contributing ,51% of the catch (Table 4). (Between June 2006 and July 2009, observers were deployed on 149, often multiday, fishing trips within the GBRWHA. Observations were on 1188 separate net shots during 297 days onboard vessels, giving a total of 1452 km-net-hours (Table 2).)
Galeocerdo cuvier (Tiger Shark)
Status: Near Threatened
The Tiger Shark (Galeocerdo cuvier) is caught regularly in target and non-target fisheries. There is evidence of declines for several populations where they have been heavily fished, but in general they do not face a high risk of extinction. However, continued demand, especially for fins, may result in further declines in the future.
Tiger Sharks are undoubtedly caught by recreational fishers in many countries, and not only those documented above. Recreational fishing is likely to account for significant mortality in Tiger Shark populations in coastal waters of some countries.
There are no specific conservation or management measures in place for the Tiger Shark.
(Between June 2006 and July 2009, observers were deployed on 149, often multiday, fishing trips within the GBRWHA. Observations were on 1188 separate net shots during 297 days onboard vessels, giving a total of 1452 km-net-hours (Table 2).) In this trip, they caught 20 tiger sharks.
Other species (e.g. Galeocerdo cuvier, Sphyrna mokarran) are absent from close inshore waters whereas adults are present (Hueter and Tyminski 2007). The wide variety of life-history characteristics and space utilisation means inshore shark populations are likely to be affected in a range of different ways and to varying extents by anthropogenic influences such as fishing. (Evaluating catch and mitigating risk in a multispecies, tropical, inshore shark fishery within the Great Barrier Reef World Heritage Area)
Negaprion acutidens (Sharptooth Lemon Shark)
Status: Vulnerable
They are particularly susceptible to local depletion due their very small habitat range and limited movement patterns (Stevens 1984).
Furthermore, evidence of local extinctions in India and Thailand (L.J.V. Compagno, pers. comm.) indicates that this species is extremely susceptible to local inshore fisheries.
There are currently no conservation measures in place for this species.
East Coast Inshore Finfish Fishery
Approximately 25 species were least likely to be sustainable in the ECIFF (Figure 6.5-7 of Salini et al 2007). Of these, 14 species had susceptibility and recovery ranks above 2.33 and were the least sustainable species in this fishery. These species include Negaprion acutidens.
Cumulative risk assessment for all northern Australian fisheries
Sawfishes were the least sustainable group with all four species having the highest susceptibility ranks due to the fact that they are captured by prawn and fish trawls, gill nets and long lines**. Other species that were least likely to be sustainable*** were N. acutidens.
Approximately 25 species were described as ‘least likely to be sustainable’ in the ECIFF (see Attachment 3 – Table 2). These species include: Negaprion acutidens.
Rhizoprionodon taylori (Australian Sharpnose Shark)
Status: Least Concern
Caught frequently by inshore demersal gillnet fisheries off Papua, but rarely elsewhere. Utilized for its fins and meat (Ref.58048). Too small to be of any commercial importance
Triaenodon obesus (Whitetip Reef Shark)
Status: Near Threatened
Formally it was abundant over coral reefs, these sharks numbers are at lower levels than those found prior to widespread expansion of fishing in the past 20 years. The species' restricted habitat, depth range, small litter size and moderately late age at maturity suggest that with increasing fishing pressure this species may become threatened.
they may attain sexual maturity at eight to nine years and live to about 16 years.
heavy fishing pressure inshore and lack of management plan in most places suggest that this species may be under threat in heavily fished areas, including remote tropical reefs (Anderson et al.1998).
of the 200 vessels operating in the ECIFF, each one is limited to take only 1 white tip reef shark, per trip.
Meat and liver utilized fresh for human consumption (Ref. 244). The liver of this shark has been reported as toxic- meat with ciguatera poisoning!
Table 3. Species of sharks and rays identified by the Scientific Advisory Group of the Inshore Finfish Management Advisory Committee in February 2007 as high or moderate risk*. Triaenodon obesus: HIGH RISK!
There are a number of chondrichthyan species that are asso- ciated almost exclusively with coral reefs, including the whitetip reef shark (Triaenodon obesus), blacktip reef shark (Carcharhinus melanopterus), grey reef shark (Carcharhinus amblyrhynchos) and Caribbean reef shark (Carcharhinus perezi) (Compagno, 1984). These species may be more susceptible to exploitation and changes in habitat quality than species that range broadly amongst habitats because of their high level of habitat association (Wetherbee et al., 1997; Garla et al., 2006a). Reef associated shark species often have complex distributions, however, making the interpretation of data associated with them complex. There has been a range of studies on coral reef associated shark species, including life his- tory (Randall, 1977; Stevens, 1984; Robbins, 2006; Heupel and Bennett, 2007), distribution (Wetherbee et al., 1997; Pikitch etal., 2005; Papastamatiou et al., 2006), density (Friedlander and DeMartini, 2002; Stevenson et al., 2007) and behaviour (Johnson and Nelson, 1973; Randall and Helfman, 1973; Nelson et al., 1986; Economakis and Lobel, 1998) but there is little information avail- able on interactions between fisheries and these species or the status of populations.
Hemipristis elongata (Snaggletooth Shark)
Status: Vulnerable
There is no information on the age at maturity and growth of this species.
Recent species composition and catch data for fisheries within its range are required to assess the population trends, especially in areas where there is a very high level of fishing pressure.
Hemigaleus australiensis (Australian Weasel Shark)
Status: Least Concern
Sphyrna mokarran (Great Hammerhead Shark) , the great hammerhead shark (Sphyrna mokarran) was the third largest component of the total weight
Status: Endangered
Sphyrna mokarran is highly valued for its fins (in target and incidental fisheries), suffers very high bycatch mortality and only reproduces once every two years, making it vulnerable to over-exploitation and population depletion.
Although there is very little species specific data available, the absence of recent records give cause to suspect a decline of at least 80% in the past 25 years. Difficulties in species identification and accurate recording make an assessment of this species very difficult, however low survival at capture makes it highly vulnerable to fishing pressure, whether directed or incidental.
A large increase in the illegal, unregulated and unreported (IUU) fishing in northern Australia in the last few years points to great concern that this species is being increasingly targeted for its valuable large fins. Recent Risk Assessments of northern Australian elasmobranchs indicate that it may be ?high-risk? however, due to a lack of data to form the basis of an accurate assessment, the species is considered Data Deficient in Australia at the present time. Further investigation of its status there is required. Given its vulnerability to depletion, low survival at capture and high value for the fin trade this species is considered to meet the criteria for Endangered globally based on the available evidence for declines of >50%. There is an urgent need for data collection in other parts of its range, but considering the high value of its fins and high fishing pressure in other parts of its range, similar declines are likely to have occurred elsewhere.
There are no known species specific conservation measures in place for S. mokarran.
East Coast Inshore Finfish Fishery
Approximately 25 species were least likely to be sustainable in the ECIFF (Figure 6.5-7 of Salini et al 2007). Of these, 14 species had susceptibility and recovery ranks above 2.33 and were the least sustainable species in this fishery. These species include S. mokarran.
Cumulative risk assessment for all northern Australian fisheries
Sawfishes were the least sustainable group with all four species having the highest susceptibility ranks due to the fact that they are captured by prawn and fish trawls, gill nets and long lines**. Other species that were least likely to be sustainable*** were S. mokarran.
Table 3. Species of sharks and rays identified by the Scientific Advisory Group of the Inshore Finfish Management Advisory Committee in February 2007 as high or moderate risk*. High risk: Sphyrna spp.
The scalloped hammerhead (Sphyrna lewini) was a significant part of the Queensland shark catch (18 per cent of commercial catch in the ECIFF during observer trips, Attachment 3), and is one of the species that risk assessments by QDPI&F and CSIRO have identified as having a high sustainability risk53 (see Attachment 3).
Despite being only 2.4% of the catch by number, the great hammerhead shark (Sphyrna mokarran) was the third largest component of the total weight (9.64%), owing to its large mean size at capture (Table 4). Conversely, catch by weight of some smaller species (e.g. R. acutus, R. taylori) as a proportion of total catch was lower than their respective proportion of catch by number.
Conversely, neonates of other species (e.g. Galeocerdo cuvier, Sphyrna mokarran) are absent from close inshore waters whereas adults are present (Hueter and Tyminski 2007). The wide variety of life-history characteristics and space utilisation means inshore shark populations are likely to be affected in a range of different ways and to varying extents by anthropogenic influences such as fishing.
DPI&F is considering further management options for species assessed to be at relatively high risk to their sustainability, for example scalloped hammerhead shark (Sphyrna lewini), great hammerhead shark (Sphyrna mokarran) and white-spotted guitarfish (Rhynchobatus djiddensis) (Gribble et al. 2005).
The following sustainability estimates were made by Gribble et al. (2004a) for what is thought to be the major commercially exploited species in the Queensland East Coast shark fishery: highest relative risk to sustainability: Sphyrna mokarran (great hammerhead shark) and Rhynchobatus djiddensis (white-spotted guitarfish).
Sphyrna corona (Scalloped Bonnethead)
Status: Near Threatened
Sphyrna media (Scoophead Shark)
Status: Data Deficient
Sphyrna tiburo (Bonnethead Shark)
Status: Least Concern
Sphyrna tudes (Smalleye Hammerhead Shark)
Status: Vulnerable
Sphyrna zygaena (Smooth Hammerhead)
Status: Vulnerable
Dasyatis fluviorum (Estuary Stingaree)
Status: Vulnerable
Very little is known of its biology and ecology. The species is still relatively common in some southern Queensland estuaries and bays (Hervey Bay, parts of Moreton Bay), and these areas may be important for habitat protection (they are however, also heavily fished both commercially and recreationally and face development pressure).
Unidentified ray
Manta spp.
12 species listed, all listed as either…
near threatened, data deficient, or endangered.
Mobula spp.
9 species of mobula:
all listed as either:
near threatened, data deficient, or endangered.
Aetobatus narinari (Spotted Eagle Ray)
Status: Near Threatened
Inshore habitat and hence availability to a wide variety of inshore fishing gear (beach seine, gillnet, purse seine, benthic longline, trawl etc.), its marketability and the generally intense and unregulated nature of inshore fisheries across large parts of the species. Overall, pressure on the species is high and likely to cause population depletions. Management and conservation measures considering harvest and trade management need to be implemented immediately.
Aetomylaeus nichofii (Banded Eagle Ray)
Status: Vulnerable
Given actual (and increasing) levels of exploitation, rarity, low fecundity and global declines in catches of batoids the species is listed as Vulnerable. Research urgently needs to address biology and levels of abundance.
There are no current conservation measures in place for A. nichofii. The species may be protected in small areas of the Great Barrier Reef Marine Park in Australia, although commercial fishing is still permitted in the majority of the park.
Aetomylaeus vespertilio (Reticulate Eagle Ray)
Status: Endangered
Uncommon eagle ray which has not been sighted in any great numbers since its description more than 160 years ago. This species would be highly susceptible to a variety of fishing methods in regions where the level of exploitation of marine resources is very high and is increasing (e.g., India, Thailand, Taiwan and Indonesia).
Highly susceptible to a variety of inshore demersal fisheries, including trawls, gillnets and trammel nets which operate intensively throughout its range
Rhinoptera neglecta (Australian Cownose Ray)
Status: Data Deficient
Little known cownose ray, possibly endemic to Australia. It is presumably taken as bycatch, particularly by gill net fisheries that overlap with its distribution. However, the extent of catches is unknown. On this basis, it is currently assessed as Data Deficient.
Unidentified eagle ray
Glaucostegus typus (Common Shovelnose Ray)
Status: Vulnerable
in Asia and the fins from large animals fetch particularly high prices, creating a significant incentive for bycatch to be retained. Very little is known about the biology or population status of this species. Given its susceptibility to capture by multiple fishing gear types, including trawl nets, gillnets and hooks and its high value fins, it is probable that numbers have been locally reduced by fishing throughout its range.
the high value placed on fins (even in Australia) the Australian population may meet the criteria of Vulnerable A2d, but more detailed catch data is required and it is thus assessed as Near Threatened in Australian waters.
The fins from Rhinobatos typus are widely considered as being amongst the most valuable of elasmobranchs (i.e., white-fin) and there is a significant incentive for fishers to remove the fins from large individuals when they are taken as either target catch or bycatch.
Further research into the population structure, biology and ecology of Rhinobatos typu is required to assess the extent to which fishing pressure, particularly in relation to finning, and habitat destruction is influencing this species within its range. Improved species composition data from all fisheries that take shovelnose rays and guitarfish is necessary.
Very little is known about the biology or population status of this species.
Rhynchobatus australiae (White-spotted Guitarfish)
Status: Vulnerable
Further investigation into the taxonomy of this species in this region is required to be able to make a more accurate assessment. There is no published information on the age and growth and natural mortality of Rhynchobatus australiae.
Rhynchobatus australiae is one of the most sought after elasmobranchs in southeast Asia (particularly Indonesia), with the dorsal fins and upper caudal fin considered to be of premium quality and fetch the highest prices (Chen 1996). A set of fins from a single individual have been reported to have fetched up to Rp 900 000 or US$396/kg (Chen 1996). The skins and flesh are also of good quality.
Anoxypristis cuspidate (Knifetooth Sawfish, Narrow Sawfish, Pointed Sawfish)
Red List Category & Criteria: Critically Endangered
(the classification just before endangered in the wild)
K-selected life history have caused substantial reductions in abundance, the fragmentation of remaining populations and the virtual disappearance of this species from commercial catches in regions where it was once considered fairly common
Conservation Actions: Also found within the Great Barrier Reef Marine Park.
Due the virtual disappearance of this species from commercial catches in regions where it was once considered fairly common, the global population of this species is considered to be much less than 80% of its former levels 30 to 50 years ago.
The principal threat to all sawfishes is fisheries, both targeted and bycatch, commercial and subsistence. Their morphology, particularly the long tooth-studded saw, makes them extraordinarily vulnerable to entanglement in any sort of net gear, including primitive fishing technology, and regardless of population size (which was probably always fairly small). When sawfish are taken in bycatch, they are often retained (particularly in areas where there is no legal protection) because of the very high value of their products (meat is high quality and fins and rostral saws extremely valuable in international trade). They are also targeted opportunistically for the same reasons.
Pristis zijsron (Narrowsnout Sawfish)
Status: Critically Endangered
The genus Pristis is taxonomically chaotic with uncertainty regarding the true number of valid species (Compagno and Cook 1995a). The practical difficulties associated with resolving these taxonomic issues are acute, since it is extremely difficult to obtain specimens or tissue samples from these increasingly rare species for taxonomic research. P. zijsron is a member of the ?Pristis pectinata complex?, probably also containing P. clavata, with narrow-based, less tapered, lighter rostral saws, with more numerous (usually over 23), smaller teeth than species of the Pristis pristis complex.
Like all sawfishes, it is extremely vulnerable to capture by target and bycatch fishing throughout its range, which has contracted significantly as a result. All populations are now very seriously depleted, with records having become extremely infrequent over the last 30 to 40 years.
This species may occur in the Great Barrier Reef Marine Park, Australia.
Listed as Endangered by the Australian Society for Fish Biology.
Nominated and considered for listing as Vulnerable under the Commonwealth's Endangered Species Protection Act 1992, but listing not made because of lack of information.
Actions needed: Strict legal protection throughout range; monitoring of bycatch; collection of biological and demographic data from accidental captures and aquarium specimens.
This is the largest sawfish species, growing to at least 5 m and possibly over 7.3 metres long.
The record of seven green sawfish (Pristis zijsron) in the catch indicates this species is still present on the east coast of Queensland at least as far south as the Whitsundays (208S), even though it is now considered to be extinct in New South Wales waters (Fisheries Management Act 1994, NSW, No. 38).
East Coast Inshore Finfish Fishery
Approximately 25 species were least likely to be sustainable in the ECIFF (Figure 6.5-7 of Salini et al 2007). Of these, 14 species had susceptibility and recovery ranks above 2.33 and were the least sustainable species in this fishery. These species include Pristis zijsron.
Table 3. Species of sharks and rays identified by the Scientific Advisory Group of the Inshore Finfish Management Advisory Committee in February 2007 as high or moderate risk*. High risk: Pristis spp.
The CSIRO risk assessment of target and by-catch fisheries to sharks and rays in Northern Australia provided fishery-level assessments, including for the ECIFF, plus a cumulative risk assessment for all northern Australian fisheries. Approximately 25 species were described as ‘least likely to be sustainable’ in the ECIFF (see Attachment 3 – Table 2). These species include: Pristis zijsron.
Stegostoma fasciatum (Leopard Shark)
Status: Vulnerable
Taken in inshore fisheries (demersal trawls, floating and fixed bottom gillnets and baited hooks) and seen in fish markets in Indonesia, Thailand, Malaysia, Philippines, Pakistan, India, Taiwan, and elsewhere. There are limited data on population declines in these areas, with the exception of the Gulf of Thailand, but the species is susceptible to local inshore fisheries and coral reef habitat loss and damage because of its habitat preferences and limited dispersion.
In Australia, where this species is abundant, has a wide distribution and is captured only in very small numbers in prawn trawls, it is assessed as Least Concern.
Apart from baited hooks, S. fasciatum is susceptible to capture in a wide range of inshore fisheries. This, in combination with a narrow habitat range and limited dispersal makes this species vulnerable to population decline.
Chiloscyllium punctatum (Brownbanded Bamboo Shark)
Status: Near Threatened
Within Australia the species is assessed as Least Concern as a portion of its habitat is protected in marine parks and it is not a target species, except perhaps for the aquarium trade. It is an extremely hardy species that would presumably survive as a discard in any trawl bycatch. However, throughout much of the rest of its range, the species is likely to be threatened by overfishing for human consumption, habitat loss due to destructive fishing methods on coral reefs, and collection for the display-aquarium trade. It fails to meet the criteria for Vulnerable due to insufficient data, but is assessed as Near Threatened globally because of concern over the significant impact that these practices must be having on this species in much of its range.
Damage and destruction of coral reef habitat from dynamite fishing, other destructive fishing practices and pollution are known to be widespread in large parts of its range.
The species is protected in a significant proportion of its range on the east coast of Australia in the Great Barrier Reef Marine Park and the Moreton Bay Marine Park. While fishing is still allowed in most areas of the parks, the species is not targeted and is likely to survive capture as bycatch.
Brachaelurus colcloughi (Bluegrey Carpetshark)
Status: Vulnerable
The Bluegrey Carpetshark (Heteroscyllium colcloughi) is a rare to uncommon species, endemic to the east coast of Australia and with a poorly known biology. Fewer than 20 specimens of this small, attractive but poorly known shark are recorded, mostly from inshore waters of Moreton Bay, Queensland. This shark seems to be rare as far as is known, despite coverage of available habitat. As presently known it has an extremely limited geographic and bathymetric range off Queensland and occurs in waters that are heavily utilised by people and which are subjected to intensive fisheries.
Age at maturity, average reproductive age and longevity are all unknown (Compagno 2001). The behavioural ecology of this shark needs to be investigated. Studies should include underwater census and tagging.
Bluegrey Carpetsharks are caught as limited inshore bycatch of fisheries and exploited at low levels for the marine aquarium trade. No information is available on trends in numbers or range, but they are not found in quantity at any locality despite reasonable survey coverage. Habitat degradation could become a problem as human usage of coastal waters increases, since it has a restricted distribution to areas heavily utilized by humans.
Only limited areas of its habitat are protected on the Great Barrier Reef, and the species is not directly protected.
REFRENCES:
International Union for Conservation of Nature and Natural Resources.
Red list of threatened species.
POSITION STATEMENT
Great Barrier Reef Marine Park Authority Position Statement on the conservation and management of sharks and rays in the Queensland East Coast Inshore Finfish Fishery
This Great Barrier Reef Marine Park Authority Position Statement in relation to the Queensland East Coast Inshore Finfish Fishery was developed in June 2007.
