The IUCN/SSC Shark Specialist Group
Shark News 1: June 1994
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Bibliography: technical reports
This section is intended to present brief notes on specialist publications
which may not otherwise come to the notice of many. Readers are invited
to send details of such reports to the Editors for inclusion in future issues.
Please include information on how the publication may be obtained.
Several of the following are summaries of unpublished reports
produced by regional sub-groups of the Shark Specialist Group. Copies
of these are available from Merry Camhi at the address on page 8.
Conservation Biology ofElasmobranchs
S. Branstetter, Editor, 1993. NOAA Technical Report NMFS 115. 99 pp.
This volume features the proceedings of the 1991 AES symposium
"Conservation Biology of Elasmobranchs". It contains nine articles covering
& variety of topics concerning biology, fisheries and public education,
including the following:
Applegate, S.P., F. Soltelo-Macias, and L. Espinosa-Arrubarrena.
1993. An overview of Mexican shark fisheries, with suggestions for shark
conservation in Mexico.
Martin, L. 1993. Shark conservation-educating the public.
Musick, Branstetter and Colvocoresses. Trends in shark abundance,
1974-1990, for the Chesapeake Bight region of the US mid-Atlantic
coast.
Shark fisheries in the Maldives
A review by R.C. Anderson and Hudha Ahmed. Ministry of Fisheries and
Agriculture, Male, Republic of Maldives, and Food and Agriculture
Organisation of the United Nations, 76pp. 1993.
This review was carried out to assess and resolve a number of
problems affecting the Maldivian shark fisheries, including suggestions of
overfishing of the valuable deep-water gulper shark (or spiny dogfish)
resource; conflict between fishermen catching shark and those targeting
other resources; and complaints from the tourism industry about the
reduction of shark numbers at particular 'shark diving' sites.
The report describes the three main shark fisheries in the Maldives:
a deep-water longline fishery for gulper shark (which yields oil for export),
an offshore longline fishery for oceanic shark, and an inshore gillnet,
handline and longline fishery for reef and other atoll-associated sharks
(both yielding fins and meat for export). The first appears to be heavily
fished and would benefit from some control, the second is small and
could beexpanded, and the last would probably run the risk of overfishing
if expanded very much more.
Reef shark fisheries are a source of conflict with the important tourism
industry. 'Shark watching' is a major activity among tourist divers. It is
roughly estimated that this generates US$2.3 million per year in direct
diving revenue, and that a grey reef shark may be worth at least one
hundred times more alive at a dive site than dead on a fishing boat.
Various recommendations are made for the management and development
of commercial shark fisheries in the Maldives and for resolving conflicts
between the tourism industry and shark fishermen. These include a
complete ban on fishing at the most important dive site in the islands and
the protection of the whale shark. These recommendations are currently
being considered by the Ministry.
The Status of the Elasmobranch Fisheries in Europe
Report of the Northeast Atlantic Subgroup of the IUCN Shark Specialist
Group. Ramon Munoz-Chapuli, Giuseppe Notarbartolo di Sciara,
Bernard Seret & Matthias Stehmann. June 1993. (Unpublished report.)
23 pp.
This report is based on a questionnaire sent to countries around the
Atlantic and Mediterranean. The most significant result is perhaps the
discovery of the extreme shortage of knowledge concerning these
fisheries. Of the 13 countries declaring a targeted elasmobranch fishery,
and six declaring shark by-catches, only eight collect shark fishery data,
and only one collects data which distinguishes between species. The
paucity of data makes stock assessment virtually impossible, a situation
which is of particular concern considering the special reproductive
biology of elasmobranchs. Most species are slow to reach maturity (up to
15 years for larger species), have long periods of gestation (or development
for oviparous species) and produce only small numbers of offspring.
Evidence of decline in populations of rays throughout the region, decline
in Mustelus catches in the Mediterranean, and concern over the expected
increase in spiny dogfish catches all highlight the need for further
investigation and control of this little-understood fishery.
The report concludes that while the elasmobranch fishery in the
region has not yet collapsed, a number of important measures are
required to prevent this from occurring.
There is a need for improved statistical data, and more intensive
research on the role of shark ecology - particularly reproductive biology
and population dynamics, and on catch trends.
Size restrictions and total allowable catches should be established for
more sensitive species such as the spiny dogfish (or spurdog) Squalus
acanthias, Mustelus species, and skates and rays.
Finally, there needs to be effective control of the use of large-scale
pelagic driftnets which indiscriminately capture all species of
elasmobranchs, includina small specimens.
The Status of the Chondrichthyan Resources in
the South West Pacific
Report of the South West Pacific Subgroup of the IUCN Shark Specialist
Group. John Stevens (compiler). 1993. (Unpublished report.) 50 pp.
The report notes that data on chondrichthyan fishery landings and
distributions within the south west Pacific region were most readily
available, and more reliable, from Australia and New Zealand. Both
countries have relatively well regulated fisheries with co-ordinated
logbook and catch and effort data recording systems, particularly for
more recent years. However, even for these countries effort data in
particular are not always readily accessible. The report is based on
preliminary information obtained from IUCN members in Australia, New
Zealand and the Solomons. Data for some countries, particularly Indonesia,
are very difficult to obtain.
The status of chondrichthyans in the region are dealt with on a
country by country basis under five general headings: targeted commercial
fisheries, by-catch in other commercial fisheries, beach protection
meshing programmes, recreational fisheries, and other concerns,
In Australia, five main chondrichthyan species are targeted by
commercial fishing (school Galeorhinus galeus, gummy Mustelus
antarcticus, whiskery Furgaleus macki, dusky whaler Carcharhinus
obscurus and blacktip sharks - mainly Carcharhinus tilstoni and C.
sorrah). These targeted fisheries are all currently subject to management
controls aimed at reducing or holding catches at sustainable levels.
Chondrichthyans taken in large quantities as by-catch in othor
fisheries (or targeted on a relatively small scale) are sawsharks (Pristiophorus
spp.), elephant fish (Callorhynchus milii), angel shark (Squatina australis),
dogfish (Squalus, Centrophorus, Centroscymnus and Deania spp.), blue shark (Prionace glauca), wobbegongs (0rectolobus spp.), and skates and
rays. Virtually nothing is known of stock structure, stock size or population
dynamics of any of these species.
Currently, the species most at risk would appear to be deep-water
dogfish and blue shark. Some species of Squalus and Centrophorus are
now being targeted and large quantities of several deep-water species
are taken by vessels fishing for orange roughy. Although some are
landed for squalene oil extraction much of the catch is discarded and
not reported. The productivity of these deep-water squalid resources
is almost certainly low in view of what is known of their biology from
other areas.
Blue sharks are taken in large numbers as by-catch in Australian
waters. The current very limited markets for the flesh in Australia and
regulations effectively prevent the fins from being retained. Almost all the
sharks come up alive on the longlines and while many are released a large
proportion are killed. Outside the AFZ the majority of blue sharks caught
by longliners are finned and the carcasses discarded. While blue shark
stocks are likely to be relatively productive they are undoubtedly being
caught on a massive scale throughout the south west Pacific region.
The annual catch of skates and rays is largely unknown. Estimates
suggest that some 2,000 tonnes were taken annually in the late 1980's as
by-catch of the northern prawn fishery alone. In most cases, data are not
even available on the species composition of the catch.
Other species whose status requires careful monitoring are whale
sharks Rhincodon typus, freshwater sawfish Pristis microdon, white shark
Carcharodon carcharias, and grey nurse Carcharias taurus.
In New Zealand, school, gummy Mustelus lenticulatus, elephant fish
and white-spotted spurdog S. acanthias are targeted commercial species
and are managed under a system of Individual Transferable Quotas
aimed at holding catches at suslainable levels. As in Australia, blue shark,
deep-water dogfish and skates and rays are taken in large numbers as by-
catch and the status of their stocks must be considered uncertain.
Data from other south western Pacific countries are poor. Anecdotal
evidence suggests that the status of some shark stocks in Indonesia should
be viewed with concern, as should the by-catch of pelagic sharks from
foreign fleets fishing elsewhere in the south west Pacific region.
Status of shark populations in the western North
Atlantic
Abstract of the IUCN Shark Specialist Group Northwest Atlantic Working
Group, Report 1993, chaired by George H. Burgess, Florida Museum of
Natural History, University of Florida, Gainesville, Florida USA 32611.
22 pp.
The IUCN/SSG Northwest Atlantic Region extends from western
Greenland southward to the Brazilian border. Major shark fisheries are
found in waters of Mexico, Trinidad and Tobago, and the United States.
Since 1976 an average of 9,249 metric tonnes (t) per year of sharks has
been harvested in Mexican waters, with declines in catches reported
since a peak of 16,236t in 1985. It is thought that Mexican waters may
support a sustainable yield of 10-12,000t/year. In Trinidad and Tobago
catches have averaged 1,016t/yr since 1972 with a peak of 1,995t in
1977. Stock assessments are not available for either Mexico or Trinidad
and Tobago shark populations, and no management regimes are in effect.
Shark catches in US North Atlantic waters have averaged 8,850t since
1979. Marine fisheries management in United States waters is exclusively
vested to the National Marine Fisheries Service (NMFS). The NMFS
estimates maximum sustainable yields (MSY) of 3,800 dressed t for large
coastal sharks (LCS), 2,590t for small coastal sharks (SCS) and 1,560t for
pelagic sharks (PS) of this region. Of these, the NMFS considers only the
LCS group overfished. On April 26, 1993 a NMFS Fishery Management
Plan (FMP) was enacted for 39 species of sharks in the Atlantic waters of
the United States. Key features of the recovery plan include annual
capture quotas of 2,900t of LCS and 1,560t of PS, and a recreational bag
limit of four LCS/PS per boat per trip. By May 15 1993 the commercial
fishery for LCS was closed, the half-year quota of 1,218t having been
reached. The second half-year began on July 1, and the commercial
fishery was again closed on July 31 after filling the quota. Recreational
bag limits are expected to have little effect on recreational anglers. The
FMP is considered overly optimistic because it considers maximum
annual production estimates used in modelling as sustainable, fails to
utilise pre-1986 data (that indicate overfishing as early as 1980) and
available fishery-independent studies in developing its assessment,
assumes unrealistically high annual survival rates from birth (0.97), and
probably underestimates the catch of SCS. While the implementation of
the FMP is a welcome first step, NMFS's projection of rebuilding and
recovery to MSY levels in two years is absurd when compared to
historical stock recoveries measured in decades.
In summary, the conclusion is that shark populations in the western
North Atlantic appear to be declining primarily as a result of overfishing.
More aggressive reductions of catches are needed under the US FMP. In
certain other areas shark populations are probably fully fished or have
become overfished, but no management is occurring.
(Editor's note: on May 13, NOAA/NMFS announced that the semiannual
commercial fishery quota for large coastal sharks for the period January
1, 1994, through June 30 will be reached by 17 May, and the fishery was
closed on that date. It will reopen on July 1st.)
Preliminary Report for the Subequatorial African
Region, Atlantic, Indian and Antarctic Oceans
Abstract of the IUCN Shark Specialist Group Subequatorial African
Region Report. L.J.V. Compagno, with input from M. J. Smale, S.F.J.
Dudley and S.F. Cook. November 1993. (Unpublished report.)
The Subequatorial African Region is somewhat arbitrarily defined as
that part of Africa below the equator, which is bordered on the west by
the southeastern Atlantic, and on the east by the southwestern Indian
Ocean, and to the south by the Antarctic Ocean and Continent. Its
longitudinal limits are 10°W to 70°E. The Region includes the coasts of
Gabon, Congo Republic, Zaire, Angola, Namibia, South Africa,
Mozambique, Tanzania, and most of Kenya on the African Continent,
plus Madagascar, a section of Antarctica from Maudheim to the Mawson
Coast, and several islands in the South Atlantic, Southern Indian, and
Antarctic Oceans.
The Region forms a major faunal province and a centre of diversity
for marine cartilaginous fishes, with approximately 260 species of sharks,
rays and chimaeras of which approximately 79 (30%) are endemics. The
high endemicity of the fauna, coupled with virtually no fisheries regulation,
accelerating fisheries and other marine activities by humans, and localized
marine habitat degradation make for considerable urgency in addressing
the rational exploitation and conservation of regional chondrichthyans.
The diversity and conservation status of regional cartilaginous fishes
are discussed, including present fisheries, conservation problems, and
conservation strategies. A checklist of regional species, a data matrix with
localities, distributional pattern, habitat, and ecomorphotype, and a
bibliography of the area are included in the report.
Other recent papers
Hanan, D.A., D.B. Holts, and A.L. Coan, Jr. 1993. The California drift
gill net fishery for sharks and swordfish, 1981-82 through 1990-91.
California Department of Fish and Game, Fish Bulletin 175. 95 pp.
Marine Technical Information Center, CA Dept. Fish and Game, 33C
Golden Shore, Suite 50, Long Beach, CA 90802, USA.
Ishihara, H., H.Homma, Y.Takeda, and J.E. Randall. 1993. Redescription
distribution, and food habits of the Indo-Pacific dasyatid stingray
Himantura granulata. Japanese journal of Ichthyology. 40(1): 23-28.
Parsons, G.R. 1993. Geographic variation in reproduction between
two populations of the bonnethead shark, Sphyrna tiburo.
Environmental Biology of Fishes 38: 25-35. G.R. Parsons, Dept. Biol.,
Univ. Miss., University, MS 38677, USA.
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