Incidental shark and ray capture occurs in longline, purse seine and gillnet tuna fisheries. The most effective mitigation measures for longline fisheries include deep-setting, reduced soak time, avoiding wire leaders and hook and bait changes [2], though in applying these, cross-taxa effects need careful consideration. Silky and oceanic whitetip sharks are the most common shark bycatch species in purse seine fisheries, captured mostly when vessels fish on FADs but also through entanglement in FAD netting. Limiting FAD use and modifying FAD designs and practices are the most promising mitigation methods [2]. As with cetaceans, entanglement is a significant problem in medium-scale, semi-industrial and artisanal tuna drift gillnet fisheries. There has been some success with sub-surface gillnets [3] but further validation of this technique is required. For all gear types, safe handling and release procedures have been developed which significantly reduce post-release mortality of sharks, e.g., try to avoid landing sharks onboard; instead bring them close to the vessel and cut line as close to the hook as possible to reduce the length of trailing line [1].
Recent studies have looked at physiological factors affecting post-release mortality of sharks, e.g., stationary-respiring shark species have been shown to experience lower post-release mortality rates than obligate ram-ventilators on longlines [2]. Such information helps to understand the vulnerability of different shark species and thus feeds into improved management strategies for shark bycatch.
For detailed biological and distributional data about shark species, refer to FishBase, Sharkipedia (includes abundance time-series) or Shark-References. FAO has published a series of regional catalogues describing shark/ batoid/chimeras, such as this one for the North Atlantic. Look for others in the series here. NOAA's 'Find a Species - Highly Migratory Species' has information on protection status, biology and population status, distribution, threats, conservation measures and research. See also FAO's database of management measures. Handy species ID guides can be found here.
STAGIS, a database of shark tagging FIELD STUDIES conducted in the Pacific Ocean, can be accessed here.
References
- Francis MP, Lyon WS, Clarke SC, et al (2023) Post-release survival of shortfin mako (Isurus oxyrinchus) and silky (Carcharhinus falciformis) sharks released from pelagic tuna longlines in the Pacific Ocean. Aquatic Conservation: Marine and Freshwater Ecosystems 33:366–378. https://doi.org/10.1002/aqc.3920
- Dapp DR, Huveneers C, Walker TI, et al (2016) Moving from Measuring to Predicting Bycatch Mortality: Predicting the Capture Condition of a Longline-Caught Pelagic Shark. Front Mar Sci 2:126. https://doi.org/10.3389/fmars.2015.00126
- Swimmer Y, Zollett E, Gutierrez A (2020) Bycatch mitigation of protected and threatened species in tuna purse seine and longline fisheries. Endang Species Res 43:517–542. https://doi.org/10.3354/esr01069
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Moazzam M (2019) Species composition of elasmobranchs in the surface and subsurface gillnet operation in the Northern Arabian Sea. In: IOTC - 15th Working Party on Ecosystems and Bycatch. IOTC-2019-WPEB15-13, La Saline Les Bains, Reunion Island
Sharks
3-Alpha Code | Name | Scientific Name |
---|---|---|
PTH | PELAGIC THRESHER SHARK | Alopias pelagicus |
THR | THRESHER SHARKS NEI | Alopias spp. |
BTH | BIGEYE THRESHER SHARK | Alopias superciliosus |
ALV | COMMON THRESHER SHARK | Alopias vulpinus |
CHB | GHOST SHARK | Callorhinchus milii |
RSK | REQUIEM SHARKS NEI | Carcharhinidae |
CVX | GROUND SHARKS | Carcharhiniformes |
ALS | SILVERTIP SHARK | Carcharhinus albimarginatus |
CCA | BIGNOSE SHARK | Carcharhinus altimus |
CCY | GRACEFUL SHARK | Carcharhinus amblyrhynchoides |
AML | GREY REEF SHARK | Carcharhinus amblyrhynchos |
CCF | PIGEYE SHARK | Carcharhinus amboinensis |
BRO | BRONZE WHALER SHARK | Carcharhinus brachyurus |
CCB | SPINNER SHARK | Carcharhinus brevipinna |
CCD | WHITECHEEK SHARK | Carcharhinus dussumieri |
FAL | SILKY SHARK | Carcharhinus falciformis |
CCZ | CREEK WHALER | Carcharhinus fitzroyensis |
CCG | GALAPAGOS SHARK | Carcharhinus galapagensis |
CCE | BULL SHARK | Carcharhinus leucas |
CCL | BLACKTIP SHARK | Carcharhinus limbatus |
OCS | OCEANIC WHITETIP SHARK | Carcharhinus longimanus |
CCM | HARDNOSE SHARK | Carcharhinus macloti |
BLR | BLACKTIP REEF SHARK | Carcharhinus melanopterus |
DUS | DUSKY SHARK | Carcharhinus obscurus |
CCP | SANDBAR SHARK | Carcharhinus plumbeus |
CCQ | SPOTTAIL SHARK | Carcharhinus sorrah |
CCU | AUSTRALIAN BLACKTIP SHARK | Carcharhinus tilstoni |
CCT | GREY NURSE/ SAND TIGER SHARK | Carcharius taurus |
WSH | GREAT WHITE SHARK | Carcharodon carcharias |
CEU | DUMB GULPER SHARK | Centrophorus harrissoni |
CEM | SMALLFIN GULPER SHARK | Centrophorus moluccensis |
CPU | LITTLE GULPER SHARK | Centrophorus uyato |
CPS | DRAUGHTSBOARD SHARK | Cephaloscyllium isabellum |
BSK | BASKING SHARK | Cetorhinus maximus |
SCK | KITEFIN SHARK | Dalatias licha |
DCA | BIRDBEAK DOGFISH | Deania calcea |
DWS | DEEP-WATER SHARKS (NEI) | Elasmobranchii |
SKX | SHARKS, RAYS, SKATES, ETC. NEI | Elasmobranchii |
ETF | BLACKBELLY LANTERNSHARK | Etmopterus lucifer |
EUB | WINGHEAD SHARK | Eusphyra blochii |
TIG | TIGER SHARK | Galeocerdo cuvier |
GAG | SCHOOL SHARK | Galeorhinus galeus |
HAH | BRISTLY CATSHARK | Halaelurus hispidus |
HEE | SNAGGLETOOTH SHARK | Hemipristis elongatus |
HXT | SHARPNOSE SEVENGILL SHARK | Heptranchias perlo |
HDQ | BULLHEAD SHARKS | Heterodontiformes |
HEG | CRESTED BULLHEAD SHARK | Heterodontus galeatus |
SBL | BLUNTNOSE SIXGILL SHARK | Hexanchus griseus |
ISB | COOKIE CUTTER SHARK | Isistius brasiliensis |
SMA | SHORTFIN MAKO | Isurus oxyrhinchus |
LMA | LONGFIN MAKO | Isurus paucus |
MAK | MAKO SHARKS | Isurus spp. |
LMD | SALMON SHARK | Lamna ditropis |
POR | PORBEAGLE SHARK | Lamna nasus |
MSK | MACKEREL SHARKS, PORBEAGLES NEI | Lamnidae |
LMP | MEGAMOUTH SHARK | Megachasma pelagios |
CTU | GUMMY SHARK | Mustelus antarcticus |
MTL | SPOTTED ESTUARY SMOOTH-HOUND | Mustelus lenticulatus |
CNX | WHITENOSE SHARK | Nasolamia velox |
ORZ | TAWNY NURSE SHARK | Nebrius ferrugineus |
NGA | SICKLEFIN LEMON SHARK | Negaprion acutidens |
NTC | BROADNOSE SEVENGILL SHARK | Notorynchus cepedianus |
ODH | BIGEYE SAND TIGER SHARK | Odontaspis noronhai |
BSH | BLUE SHARK | Prionace glauca |
PPC | LONGNOSE SAWSHARK | Pristiophorus cirratus |
RPC | DWARF SAWFISH | Pristis clavata |
RPZ | LONGCOMB SAWFISH | Pristis zijsron |
PSK | CROCODILE SHARK | Pseudocarcharias kamoharai |
REO | SHARK SUCKER | Remora remora |
RHN | WHALE SHARK | Rhincodon typus |
RHA | MILK SHARK | Rhizoprionodon acutus |
RHY | AUSTRALIAN SHARPNOSE SHARK | Rhizoprionodon taylori |
TSK | FLAPNOSE HOUNDSHARK | Scylliogaleus quecketti |
CYU | PLUNKET SHARK | Scymnodon plunketi |
SSQ | VELVET DOGFISH | Scymnodon squamulosus |
SKH | VARIOUS SHARKS NEI | Selachimorpha (Pleurotremata) |
SON | PACIFIC SLEEPER SHARK | Somniosus pacificus |
SPL | SCALLOPED HAMMERHEAD | Sphyrna lewini |
SPK | GREAT HAMMERHEAD | Sphyrna mokarran |
SPN | HAMMERHEAD SHARKS NEI | Sphyrna spp. |
SPQ | SMALLEYE HAMMERHEAD | Sphyrna tudes |
SPZ | SMOOTH HAMMERHEAD | Sphyrna zygaena |
DGX | DOGFISH SHARKS NEI | Squalidae |
DGS | PICKED DOGFISH | Squalus acanthias |
DOP | SHORTNOSE SPURDOG | Squalus megalops |
DGZ | DOGFISHES NEI | Squalus spp |
SUN | OCELLATED ANGELSHARK | Squatina tergocellatoides |
ASK | ANGELSHARKS, SAND DEVILS NEI | Squatinidae |
OSF | ZEBRA SHARK | Stegostoma fasciatum |
TRB | WHITETIP REEF SHARK | Triaenodon obesus |
LES | LEOPARD SHARK | Triakis semifasciata |
RUT | CROSSBACK STINGAREE | Urolophus cruciatus |
RUZ | GREENBACK STINGAREE | Urolophus viridis |