A novel approach for estimation of the natural mortality of the common whelk, Buccinum undatum (L.) and role of hermit crabs in its shell turnover

Effect of temperature on the growth of the commercially fished common whelk (Buccinum undatum, L.): A regional analysis within the Irish Sea

“…It is clear, for example, that the widely adopted EU minimum landing size (MLS) (45 mm total shell length; TSL) fails to protect juvenile individuals (individuals below the size of functional maturity; L 50 ) from harvest in many regions of the British Isles (Shelmerdine, et al, 2007;Haig, et al, 2015;Emmerson, et al, 2018). The uncertainty, knowledge gaps and localised variation in basic biological parameters such as maturity (Haig, et al, 2015;McIntyre, et al, 2015), fecundity (Valentinsson, 2002) and mortality (Laptikhovsky, et al, 2016), combined with low resolution data on fishing effort and catch has meant that a conceptual framework for stock assessments has not yet been developed. As a consequence, the fishery is considered 'data-poor' and there are no biologically referrenced catch or effort restrictions.…”

Age and growth rate estimations of the commercially fished gastropod Buccinum undatum

“…Concerns are growing over the sustainability of whelk populations in certain areas as there were reports on collapses of some fished populations (Jersey - Shrives et al, 2015;Ireland -Fahy et al, 2005;North Sea/Netherlands -Ten Hallers-Tjabbes et al, 1996) although it has not been confirmed that these declines are necessarily fishery induced (Ten Hallers-Tjabbes et al, 1996). This has prompted an increase in research concerning B. undatum in recent years covering important topics such regional variation in size at maturity and maturity assessment (Haig et al, 2015;McIntyre et al, 2015;Borsetti et al, 2018;Emmerson et al, 2018); fishery based assessments of catches and population structures (Shrives et al, 2015;Woods & Jonasson, 2017;Emmerson et al, 2018); population genetics (Pálsson et al, 2014); mortality estimations (Laptikhovsky et al, 2016) and age determination (Hollyman et al, 2018a(Hollyman et al, & 2017. The ability to model stock dynamics is the keystone for all fishery management (Hilborn & Walters, 1992).…”

From coral reefs to whale teeth: estimating mortality from natural accumulations of skeletal materials

“…This in combination with known difference between natural mortality and survival will provide an estimation of fishing mortality, stock size and harvest rate. This method could be applicable only to molluscs where dead shells do not accumulate over time on fishing grounds and that are not processed at sea so dead shells are disposed somewhere else (Laptikhovsky et al 2016).…”

“…Gastropods comprise a single shell with no ligament with which to track decomposition; instead, the potential burial time was used as a timeframe (ParsonsHubbard et al 1999) for the ratio between dead and live shells in random samples by a towed gear (Laptikhovsky et al 2016). Because the shells of Bucci num undatum contain no discernible annual growth rings, the age structure of the living whelk population from the same area was used as a proxy for estimation of AD using age-length keys, determined through the analysis of annual striae on the operculum (Santarelli & Gros 1985).…”

“…When the age structure of dead shells from recent thanatocoenoses is available simultaneously with that of live molluscs, both F and M can be estimated together. It is possible that if the age structure of live molluscs reflects total mortality, and distribution of AD -natural mortality, the difference can be accounted for by fishing mortality (Laptikhovsky et al 2016). This ap proach requires a species that does not immigrate and emigrate to and from the studied area, which should be large enough to ignore hermit crab impact, and the commercial harvest being processed onshore so that no empty shells are returned to the environment to be potentially confused with those that died from natural causes.…”