Effects of a research trawl on a hard-bottom assemblage of sponges and corals

Dolah, Robert F. Van; Wendt, Priscilla H.; Nicholson, Nick

doi:10.1016/0165-7836(87)90014-2

Cited by 67 publications

(45 citation statements)

References 6 publications

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“…In the eastern Bering Sea, where both juvenile halibut and rock sole are abundant, large sessile invertebrates are significantly less abundant in trawled than in untrawled areas . Such reductions in bottom structure appear to be a common consequence of intensive trawling (Van Dolah et al 1987, Thrush et al 1998, Freese et al 1999. Our laboratory experiments, along with prior field and laboratory work (Stoner & Titgen 2003), indicate that Age-0 yr halibut and rock sole are likely to be found at higher density in low-relief habitats that have emergent structure.…”

Section: Implications For Ecosystems and Fisheriesmentioning

confidence: 66%

Behavioral mechanisms underlying the refuge value of benthic habitat structure for two flatfishes with differing anti-predator strategies

Ryer¹,

Stoner²,

Titgen³

2004

Mar. Ecol. Prog. Ser.

111

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Juvenile flatfish habitat is usually modeled on the basis of sediment grain-size, depth and temperature. Recent evidence indicates that some juvenile flatfishes associate with emergent structures such as sponge, shell and other biogenic and bed-form features of otherwise low-relief shelf habitats. In laboratory experiments we examined the habitat preference and effects of habitat structure upon predation vulnerability of sub-yearling (Age-0) Pacific halibut Hippoglossus stenolepis and northern rock sole Lepidopsetta polyxystra. When given the choice between bare sand or sand with 16% sponge coverage, halibut demonstrated strong preference for sponge, while rock sole showed no preference. Larger Age-2 halibut (used as predators in the subsequent experiment) also preferred sponge, but this preference declined with increasing hunger. When allowed to forage for Age-0 flatfishes in either bare sand or sponge, predators consumed more prey in sand and consumed more Age-0 halibut than rock sole. We were able to determine which behavioral processes in the predator-prey interaction were modified by the presence of habitat structure. Predator-prey encounter rates decreased in the sponge habitat as predator search was impeded: predators paused more frequently and swam more slowly to maneuver through the sponges. Sponges also tended to hinder the pursuit of prey. Rock sole utilized stereotypic flatfish defense-mechanisms, relying upon immobility, burial and crypsis, and were less likely to flush at a predator's approach than halibut. Halibut have a less developed ability to mimic sediments, but a deeper/narrower body that confers greater swimming speed, and were more likely to flush as a predator approached. Once they had flushed and were pursued by a predator, halibut were more likely to escape than were rock sole. These experiments support an accumulating body of evidence that emergent structure, in otherwise low-relief benthic habitats, may play an important role in the ecology of some juvenile flatfishes. Removal of emergent structure by towed fishing gear and other anthropogenic and/or natural disturbance may influence patterns of distribution for juvenile halibut, as fish redistribute to less preferred habitat, and may decrease survival rates through increased losses to predation.

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Section: Implications For Ecosystems and Fisheriesmentioning

confidence: 66%

Behavioral mechanisms underlying the refuge value of benthic habitat structure for two flatfishes with differing anti-predator strategies

Ryer¹,

Stoner²,

Titgen³

2004

Mar. Ecol. Prog. Ser.

111

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“…Other studies have shown that the type of bottom trawl gear used in New Zealand seamount fisheries has a marked impact on the bottom, with removal of benthic fauna (Probert et al 1997;Koslow et al 2001). However, the impact will depend on substrate type and community composition, as well as intensity of fishing (van Dolah et al 1987;Freese et al 1999;Pitcher et al 2000). The coral cover present on many seamounts is fragile, and easily damaged by bottom trawl gear (Clark & O'Driscoll 2003), whereas the same intensity of trawling may have a smaller impact on a softer substrate (e.g., Sanchez et al 2000).…”

Section: Discussionmentioning

confidence: 99%

Quantifying the relative intensity of fishing on New Zealand seamounts

O’Driscoll

Clark

2005

New Zealand Journal of Marine and Freshwater Research

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New Zealand seamounts support major fisheries for several deepwater fish species, including orange roughy (Hoplostethus atlanticus) and smooth oreo (Pseudocyttus maculatus). Although a high proportion of features in the depth range 500-1000 m have been fished, very little is known about the ecological impacts of bottom trawling on seamounts. The potential impact is likely to be influenced by the spatial extent and frequency of fishing. A new index is presented to assess the relative intensity of trawling on New Zealand seamounts. The fishing effects index (FEI) incorporates information on the density of fishing on the seamount as a proportion of the seabed area and also on tow direction. Detailed fisheries data from more than 250 000 tows were examined to calculate FEI for New Zealand seamounts. The most intensively fished seamounts were on the south Chatham Rise, an area characterised by a large number of relatively small features which were fished serially for orange roughy in the 1980s and 1990s. Other seamounts with high FEI were on the north Chatham Rise, Challenger Plateau, and off the east coast of the North Island. A range of sensitivity analyses indicated that the general rankings of seamounts were relatively robust to the choice of arbitrary thresholds used to assign tows to seamounts.

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“…Mar Ecol Prog Ser 430: [71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86] 2011 ficult to quantify in a systematic way owing to the difficulty of sampling fauna attached to hard substrata, variation in life-history traits (colonial versus single individuals, senescence of some hydroids in winter), variation in body form with environmental conditions and the absence of precise estimates of the frequency and intensity of fishing impacts (Van Dolah et al 1987, Henry et al 2006.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

“…caprellid amphipods on hydroids, or the fauna associated with pomatocerid tube worm heads (Kaiser et al 1999). However, the response of emergent species to fishing has proved dif-ficult to quantify in a systematic way owing to the difficulty of sampling fauna attached to hard substrata, variation in life-history traits (colonial versus single individuals, senescence of some hydroids in winter), variation in body form with environmental conditions and the absence of precise estimates of the frequency and intensity of fishing impacts (Van Dolah et al 1987, Henry et al 2006.…”

Section: Introductionmentioning

confidence: 99%

Quantification and prediction of the impact of fishing on epifaunal communities

Lambert¹,

Jennings²,

Kaiser³

et al. 2011

Mar. Ecol. Prog. Ser.

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The loss of emergent epifaunal biomass due to fishing impacts has not been quantified at the scale of an entire fishery. Here, based on an analysis of the impacts of the scallop dredge fleet around the Isle of Man, Irish Sea, we show how fishing and the physical environment act to determine the biomass and size composition of emergent epifauna. The epifauna create habitat structure that is used by juvenile scallops and other species, thus providing an important ecosystem service. Epifauna were identified and quantified based on photographs taken during an extensive survey of the territorial waters of the Isle of Man. On hard substrata, the effect of tidal velocity on total biomass (g m -2 ) and the maximum size (g) of the largest organism encountered in each taxon was positive while wave stress and fishing frequency had a negative impact. We used the results to predict the distribution of biomass and maximum size and to quantify the total effects of fishing. Fishing frequency was the most important factor that affected maximum size of the epifauna, resulting in a mean decrease in size of 17% (range 0 to 66%). Total biomass was predominantly affected by wave stress and tidal velocity while fishing caused a mean biomass decrease of 8% (range 0 to 34%), equivalent to 1.8 g wet weight m -2. The results have implications for management because they provide an assessment of the overall impact of fishing at the scale of an entire fleet and inform the identification of areas where seabed habitats are most vulnerable to fishing. KEY WORDS: Sessile benthos · Fishing impact · Environmental impact · Photographic survey Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 430: [71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86] 2011 ficult to quantify in a systematic way owing to the difficulty of sampling fauna attached to hard substrata, variation in life-history traits (colonial versus single individuals, senescence of some hydroids in winter), variation in body form with environmental conditions and the absence of precise estimates of the frequency and intensity of fishing impacts (Van Dolah et al. 1987, Henry et al. 2006.Sessile epifaunal species and other habitat-forming organisms are widely distributed on the continental shelf and display a range of life-history traits and morphological characteristics that influence the environments where they are found and their vulnerability to fishing impacts. There is limited information on growth, reproduction, mortality and the ecological requirements of the sessile species that occur in northern European waters (see BIOTIC database, MarLIN website, www.marlin.ac.uk/biotic/). The distribution of these biota is affected by substratum stability, turbidity, nutrient supply, light availability, temperature and hydrodynamical conditions that in turn affect the resilience of the habitat to fishing disturbance (Hall 1994, Jennings et al. 1999, Callaway et al. 2002. A better understanding of the relationships bet...

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Effects of a research trawl on a hard-bottom assemblage of sponges and corals

Cited by 67 publications

References 6 publications

Behavioral mechanisms underlying the refuge value of benthic habitat structure for two flatfishes with differing anti-predator strategies

Behavioral mechanisms underlying the refuge value of benthic habitat structure for two flatfishes with differing anti-predator strategies

Quantifying the relative intensity of fishing on New Zealand seamounts

Quantification and prediction of the impact of fishing on epifaunal communities

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