Sea snake by-catch of fish trawlers on the northern Australian continental shelf

During 1986-90, 206 sea snakes were collected from Taiwanese pair-trawlers (North West Shelf, 1986-87), Thai stern-trawlers (Arafura Sea, 1986-87), RV Soela (North West Shelf, 1986) and RV Clipper Bird (Timor and Arafura Seas, 1990). Taiwanese (58 specimens; 294.8 h trawled) and Thai (71 specimens; 1244 h trawled) vessels trawled in 50-75 m and caught 10 and 7 species respectively. The Soela (41 specimens; 72.5 h trawled) and Clipper Bird (36 specimens; 103 h trawled) operated in depths of 19-198 m and each caught 12 species. Hydrophines (10 species plus one specimen from an undescribed taxon) represented 68.4% of the specimens. Aipysurines (6 species) were more common in samples from the North West Shelf (46.2% of taxa, 56.6% of specimens) than from the Timor and Arafura Seas (28.6% of taxa, 11.2% of specimens). Taiwanese boats on the North West Shelf (1980-90) and Thai boats in the Arafura Sea (1985-90) were estimated to have caught 49000 (� 5600) and 10000 (� 1250) sea snakes respectively. Trawl surveys (e.g. Soela and Clipper Bird) may be unsuitable for monitoring sea snakes, because approximately 25 surveys would be needed to detect a 20% exponential decline in absolute abundance.

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Factors affecting the catch rates and relative abundance of sea snakes in the by-catch of trawlers targeting tiger and endeavour prawns on the northern Australian continental shelf

Marine and Freshwater Research ◽

10.1071/mf98134 ◽

2000 ◽

Vol 51 (2) ◽

pp. 155 ◽

Cited By ~ 7

Author(s):

T. M. Ward

Keyword(s):

Continental Shelf ◽

Relative Abundance ◽

Sampling Effort ◽

Sea Snake ◽

Factors Affecting ◽

Sea Snakes ◽

The Status ◽

By Catch ◽

Catch Rates ◽

Northern Prawn Fishery

A total of 4378 sea snakes (14 species; 5 unidentified specimens) were collected from 21 082 h of sampling effort by trawlers of the Northern Prawn Fishery. Most species (12) were collected from the southern Gulf of Carpentaria. Hydrophis elegans and Disteira major were caught frequently in all areas. The catch rates of H. elegans and Lapemis hardwickii were highest in the eastern gulf and in depths of 31–40 and <20 m respectively. Hydrophis elegans represented >27% of specimens from most areas. Other species that represented ≥20% of specimens from one or more areas were: L. hardwickii, H. ornatus, D. major and Aipysurus eydouxii. Catch rates of all species of snakes combined did not differ significantly between 1984–86 and 1989–90, and were moderately high around Groote Eylandt where the fishery is centred. Most by-catch species occur in areas that are not subjected to extensive trawling, and there are no data to suggest that this fishery seriously threatens any population of sea snake. However, sea snakes may be more vulnerable to trawler-induced effects than most other by-catch species, and formal assessment of the status of populations is needed.

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Sea snake by-catch of prawn trawlers on the northern Australian continental shelf

Marine and Freshwater Research ◽

10.1071/mf9960631 ◽

1996 ◽

Vol 47 (4) ◽

pp. 631 ◽

Cited By ~ 10

Author(s):

TM Ward

Keyword(s):

Data Collection ◽

Continental Shelf ◽

Total Catch ◽

Sea Snake ◽

Sea Snakes ◽

Cape York ◽

By Catch ◽

Penaeus Merguiensis ◽

Northern Prawn Fishery

This paper describes and compares the sea snakes caught by vessels that target tiger prawns and endeavour prawns or that target the banana prawns Penaeus merguiensis and P. indicus. In 1989-90, 5203 sea snakes (14 species; 7 unidentified specimens) were purchased from fishers who trawled between Koolan Island and Cape York and participated in a dedicated carcass-tagging and data-collection programme. Hydrophines (11 species) represented 86.7% of the total catch. Aipysurines (3 species) represented 15.0% of specimens from vessels that targeted tiger prawns or endeavour prawns, but only 1.1% of specimens from vessels that targeted the banana prawns P. merguiensis and P. indicus. Prawn trawlers that operated between Koolan Island and Cape York during 1990 caught approximately 81 080 (� 13 670) sea snakes. Vessels that targeted tiger/endeavour prawns, P. merguiensis and P. indicus caught approximately 69260 (� 8750), 7200 (� 3250) and 4620 (� 1120) sea snakes respectively. The results emphasize the advantages of interactions between fishers and scientists and the need to assess separately the impacts of the three fisheries that constitute the northern prawn fishery.

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Hardisty, J., "The British Seas: An Introduction to the Oceanography and Resources of the North-West European Continental Shelf" (Book Review)

Town Planning Review ◽

10.3828/tpr.64.2.8003231112122710 ◽

1993 ◽

Vol 64 (2) ◽

pp. 219

Author(s):

D. F. Shaw

Keyword(s):

Continental Shelf ◽

North West ◽

The North ◽

West European

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Hydrophis donaldi (Elapidae, Hydrophiinae), a highly distinctive new species of sea snake from northern Australia

Zootaxa ◽

10.11646/zootaxa.3201.1.3 ◽

2012 ◽

Vol 3201 (1) ◽

pp. 45 ◽

Cited By ~ 7

Author(s):

KANISHKA D.B. UKUWELA ◽

KATE L. SANDERS ◽

BRYAN G. FRY

Keyword(s):

New Species ◽

Habitat Preferences ◽

The Body ◽

Colour Pattern ◽

Northern Australia ◽

Nucleotide Substitutions ◽

Sea Snake ◽

Sea Snakes ◽

Morphological Diagnosis ◽

By Catch

A new species of viviparous sea snake, Hydrophis donaldi sp. nov. (Hydrophiinae), is described from the Gulf of Carpen-taria, northern Australia. Molecular analyses reveal this species as a deeply divergent lineage within the Hydrophis sub-group, and separate it from all other sampled taxa by fixed nucleotide substitutions at three independent mitochondrial andnuclear loci. The new species is assigned to Hydrophis based on the current morphological diagnosis of this large but pa-raphyletic genus, and is distinguished from all other Hydrophis species and closely allied genera by a combination of mor-phological characters relating to scalation, colour pattern and osteology. Using current keys for sea snakes, H. donaldi sp.nov. might be mistaken for H. coggeri, H. sibauensis or H. torquatus diadema but it is readily distinguished from thesespecies by a higher number of bands on the body and tail, lower ventral count, strongly spinous body scales, and a wider,more rounded head. Sea snakes have been sampled intensively in the Gulf of Carpentaria due to their vulnerability to by-catch in the region’s commercial prawn-trawl fisheries. That this highly distinctive new species has evaded discovery inthe region until now is surprising, but might be explained by its habitat preferences. All known specimens of H. donaldi sp. nov. were found in estuarine habitats that are relatively poorly surveyed and are not targeted by commercial fisheries.

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