Disturbance of benthic species by fishing activities: a sensitivity index

Abstract

1. Preliminary estimates of the relative sensitivity of sea bed types and benthic species to physical disturbance, particularly fishing activity, have been made in order to identify areas where further studies are required and to help formulate management plans for sites of marine conservation importance. 2. Physical disturbance is considered in the context of a single encounter with fishing gear followed by a recovery period during which there is no fishing, but with a view to qualifying, in the future, the effect of multiple fishing events. Disturbance is considered in terms of the physical action of the gear on the sea bed and the unit area over which this action occurs. 3. The effects of a wide range of gears are considered. Static gears, which can be employed on a variety of substrata, generally result in low level impacts for single fishing events and impacts are localized compared with the effects of mobile gears, which can extend over considerable areas. 4. The theoretical sensitivity of individual species is assessed on the basis of how well they cope with an encounter with fishing gear and on their likely recovery from destruction in terms of their reproductive strategies. 5. Species considered of key importance in the structuring of communities are suggested and examples of particularly sensitive species, which are therefore likely indicator species of physical disturbance, are listed. 6. Fragile, slow recruiting animals are considered to be most susceptible to disturbance, while the least sensitive species are generally fast growing and have good recruitment. ©1996 by John Wiley & Sons, Ltd.

Catch me in winter! Seasonal variation in air temperature severely enhances physiological stress and mortality of species subjected to sorting operations and discarded during annual fishing activities

“…Such rank could include physiological aspects based on field observation and mortality assessment, integrating former assessments mainly based on life-history and fragility features (Macdonald et al, 1996). In spite of the different mechanisms responsible for the resilience to fishing disturbance in populations of scavengers species, studies showing high discard mortality rates should be considered by the authorities to enforce the legislation aimed to reduce this adverse effect of fishing on non-target species.…”

Discard analysis and damage to non-target species in the "rapido" trawl fishery

“…As suggested by other authors (MacDonald et al 1996;Mensink et al 2000), we applied a three-level scale for damage assessment of most species: 0 no detectable damage, 1 visible damage, 2 body completely crushed.…”

“…This approach allows an evaluation of the relative fragility of non-target species, which could be an integral part of their sensitivity (sensu MacDonald et al 1996); furthermore, a ®rst estimate (underestimated and here referred to as``minimum lethal rate'') of the mortality induced by the rapido ®sh-eries can be obtained considering animals whose bodies have been completely crushed. This approach permits work on board commercial vessels, even if samples are subsequently processed in the laboratory; standardisation of methodologies seems to be easier than for survival tests, and enables comparison of the physical eects on non-target species of dierent ®shing gears, as well as the study of the eects of the same gear on species living on dierent ®shing grounds.…”

Sea pen (Pennatulacea) aggregations on the northern Spanish shelf: distribution and faunal assemblages

“…Despite their ecological value, pennatulacean coral habitats have been overlooked compared with cold-water coral ecosystems and studies of the latter mainly focus on stony corals (Order Scleractinia), sea fans and soft corals (Order Alcyonacea). Examples of sea pens forming fields (Aguilar et al 2009, Porporato et al 2014, Kenchington et al 2014) and acting as nurseries for fish larvae (Pirtle 2005, Baillon et al 2012 or as indicators of quality of mud habitats (MacDonald et al 1996) highlight their role in benthic ecosystems. Like other corals, sea pens are slow-growing species that are particularly vulnerable because recovery after disturbances can take a long time (Kaiser et al 2006, de Moura Neves et al 2015.…”