Effects of bottom fishing on the benthic megafauna of Georges Bank

Collie, Jeremy S.; Escanero, Galo A.; Valentine, Page C.

doi:10.3354/meps155159

Cited by 309 publications

(244 citation statements)

References 12 publications

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“…Hutchings 1990, Jones 1992, Auster et al 1996, Collie et al 1997, Jennings & Kaiser 1998. These studies have demonstrated a variety of trawling impacts: direct impacts on the benthic fauna and substrate, and secondary impacts, particularly on fishes, arising from reduced cover and habitat complexity.…”

Section: Discussionmentioning

confidence: 99%

“…A rapidly growing literature has shown that trawling may substantially alter marine benthic habitats and communities (Bradstock & Gordon 1983, de Groot 1984, Sainsbury 1988, Hutchings 1990, Jones 1992, Auster et al 1996, Collie et al 1997. Several studies have also demonstrated significant secondary, or indirect, impacts on elements of the community, such as juvenile or adult fishes, that utilize biogenic structures on the seafloor directly impacted by trawling (Bradstock & Gordon 1983, Sainsbury 1988.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Seamount benthic macrofauna off southern Tasmania: community structure and impacts of trawling

Koslow¹,

Gowlett-Holmes²,

Lowry³

et al. 2001

Mar. Ecol. Prog. Ser.

300

258

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The benthic macrofauna of a group of small seamounts south of Tasmania was surveyed with a dredge and camera to assess the impact of trawling for orange roughy (Hoplostethus atlanticus; Trachichthyidae) and the efficacy of a proposed marine reserve. The seamounts were generally 300 to 600 m high and the peaks ranged from 660 to 1700 m depth. The fauna was diverse: 262 species of invertebrates and 37 species of fishes were enumerated, compared with 598 species of invertebrates previously reported from seamounts worldwide. On seamounts that peaked at depths <1400 m and that had not been heavily fished, the invertebrate fauna was dense, diverse and dominated by suspension feeders, including a matrix-forming colonial hard coral (Solenosmilia variabilis) and a variety of hard and soft (gorgonian and antipatharian) corals, hydroids, sponges and suspension-feeding ophiuroids and sea stars. Of the invertebrate species, 24 to 43% were new to science, and between 16 and 33% appeared to be restricted to the seamount environment. Trawl operations effectively removed the reef aggregate from the most heavily fished seamounts. The benthic biomass of samples from unfished seamounts was 106% greater than from heavily fished seamounts and the number of species per sample was 46% greater. Living S. variabilis was not found on seamounts peaking at depths >1400 m. These seamounts were dominated by sea urchins and had lower biomass and fewer species per sample. However, few species were restricted to either the shallowest or deepest depths sampled. The fauna unique to the region's seamounts appears to be adequately represented within a recently established 'Marine Protected Area' that encloses 12 seamounts that peak at depths >1150 m.KEY WORDS: Seamount · Benthos · Impacts of trawling · Community structure 213: 111-125, 2001 rockhopper gear -large rubber bobbins and metal discs along the footrope -and precise electronic positioning systems both for the vessel and to monitor net performance. Seamounts are one such environment to become subject to intensive trawl fishing in recent decades. Resale or republication not permitted without written consent of the publisherMar Ecol Prog SerSeamounts provide a unique deep-sea environment due to the topographically-enhanced currents in their vicinity (Roden 1986). In the water column, substantial aggregations of deep-bodied fishes, such as the pelagic armourhead (Pseudopentaceros wheeleri), Sebastes spp., orange roughy (Hoplostethus atlanticus) and oreosomatids are commonly found around seamounts (Boehlert & Sasaki 1988, Koslow 1996, 1997. These aggregations are supported in the otherwise food-poor deep sea by the enhanced flux of prey organisms past the seamounts and the interception and trapping of vertical migrators by the uplifted topography (Tseitlin 1985, Genin et al. 1988, Koslow 1997. Discovery of these aggregations led to seamounts being increasingly targeted by trawlers throughout the world's oceans: i.e. the massive but short-lived fishery for pelagic armourhead in the N...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Seamount benthic macrofauna off southern Tasmania: community structure and impacts of trawling

Koslow¹,

Gowlett-Holmes²,

Lowry³

et al. 2001

Mar. Ecol. Prog. Ser.

300

258

View full text Add to dashboard Cite

show abstract

“…Mobile fish- ing gear has been shown, to directly alter the physical structure of the seafloor, reducing complexity of the substratum, including any associated epibionts (Auster et al 1996). Collie et al (1997) found higher numbers of benthic organisms, biomass, species richness and species diversity in undredged sites relative to dredged sites on the northeast peak of Georges Bank. Auster et al (1996) showed that emergent epibenthic organisms on several banks of the Gulf of Maine are easily removed by mobile fishing gear.…”

Section: Discussionmentioning

confidence: 99%

“…In a study of the effects of scallop dredging on seafloor habitat on the northeast peak of Georges Bank, Collie et al (1997) found that the numerical abundance of the emergent tube-dwelling polychaete Filograna implexa was significantly higher at undredged sites than at dredged sites. Similar results were found in the Gulf of Alaska (Freese et al 1999), with a significant decrease in density of sponges and anthozoans, as well as a n increase in damage to such organisms, in trawled areas relative to untrawled reference sites.…”

Section: Introductionmentioning

confidence: 99%

Habitat-mediated survivorship of juvenile (0-year) Atlantic cod Gadus morhua

Lindholm¹,

Auster²,

Kaufman³

1999

Mar. Ecol. Prog. Ser.

102

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ABSTRACT. Fishing activity can impact fish populations in 2 ways. The first is the immediate effect on population demographics by the removal of fish. Second is the impact of fishing (e.g. bottom trawls and dredges) on the seafloor which can reduce habitat structure and thus increase the vulnerability of juvenile fish to predation by older conspecifics and other predators. We conducted laboratory experiments to investigate the role of variability in seafloor habitat structure on the survivorship of post-settlement juvenile (0-yr) Atlantic cod Gadus rnorhua. Groups of 0-yr cod were exposed to a foraging predator (3+ cod) over 5 seafloor habitats of varying complexity (sand, cobble, minimum density short sponge, maximum density short sponge, and tall sponge). These habitats were selected to mimic the range of impacts of mobile fishing gear given a gradient in fishing effort. Emergent epifauna resulted in a significant decrease in 0-yr mortality when compared to flat sand., the least complex habitat Epifaunal density was shown to be more significant than epifaunal height in reducing 0-yr mortality Predator reaction distance decreased with increasing habitat complexity, presumably due to the obstruction of visual cues by complex relief. Latency to first and second capture did not differ statistically between habitats. Alteration of seafloor habitat by fishing activity in the northwest Atlantic could magnify the effects of overfishing by limiting juvenile survivorship.

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“…The increased abundance of lesser-spotted catshark probably results from scavenging on macrofauna, such as crustaceans and errant polychaetes (Serrano et al, 2003a(Serrano et al, , 2003b. These are taxa that benefit from disturbed sediments and organic matter generated by trawls and discards (Collie et al, 1997;Kaiser et al, 1998) including fish . Changes in the abundance and diets of these two species of catshark may be good indicators of broadscale changes caused by increasing exploitation in their ecosystem.…”

Section: Resources Exploited By Lesser-spotted Catshark and Blackmoutmentioning

confidence: 99%

Trophic Relations of Lesser-Spotted Catshark (Scyliorhinus canicula) and Blackmouth Catshark (Galeus melastomus) in the Cantabrian Sea

Olaso¹,

Velasco²,

Sánchez³

et al. 2004

J. Northw. Atl. Fish. Sci.

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The feeding habits of Scyliorhinus canicula and Galeus melastomus were investigated by analysing the stomach contents from 6 036 individuals collected on research surveys in the southern region of the Bay of Biscay during the autumns of 1988-2001. These catshark species are the most abundant scyliorhinids on the Cantabrian shelf. Their depth ranges partly overlap, although they occur in different habitats. Both catshark species are opportunistic scavengers, with their main prey being fish and crustaceans. Diets of the two species overlap; they are most similar in individuals <30 cm total length (TL) where euphausiids are important prey, but, for individuals ≥30 cm TL, fish (mainly discarded from trawlers) are important prey. Lesser-spotted catshark are mostly benthic feeders and they feed on a greater diversity of prey than blackmouth catshark, which are more suprabenthic. Resource partitioning between the two species appears to depend on the better vision of the blackmouth catshark, which feeds more in the water column whereas the better developed olfactory sense of the lesser-spotted catshark is an adaptation to benthic feeding. The broad diets of these catshark species and their consumption of fish discarded from trawlers may make them good indicators of fishinginduced change in the Cantabrian Sea ecosystem.

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Effects of bottom fishing on the benthic megafauna of Georges Bank

Cited by 309 publications

References 12 publications

Seamount benthic macrofauna off southern Tasmania: community structure and impacts of trawling

Seamount benthic macrofauna off southern Tasmania: community structure and impacts of trawling

Habitat-mediated survivorship of juvenile (0-year) Atlantic cod Gadus morhua

Trophic Relations of Lesser-Spotted Catshark (Scyliorhinus canicula) and Blackmouth Catshark (Galeus melastomus) in the Cantabrian Sea

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