Temporal changes in size‐at‐maturity of black dogfish Centroscyllium fabricii

Abstract

By examining the maturity of 283 black dogfish Centroscyllium fabricii from Greenland waters, a shift in size-at-maturity in both sexes over the past 25 years is observed.Size-at-first maturity decreased approximately 10 cm in both sexes, and L 50 and L 95 shifted similarly in males, but not in females. It is argued that bycatch in the Greenland halibut Reinhardtius hippoglossoides fishery has contributed to the observed shift, but also emphasised that such a distinct change could have a methodological component as well as being subject to effects of environmental change. K E Y W O R D S black dogfish, bycatch, Centroscyllium fabricii, deep sea fishery, maturity ogive, shark The black dogfish Centroscyllium fabricii (Reinhardt 1825) is a deep-

Distinct latitudinal community patterns of Arctic marine vertebrates along the East Greenlandic coast detected by environmental DNA

“…There is currently very little information on the fisheries' impact on bycaught vertebrate species, as well as on the distribution and abundance of populations of noncommercial vertebrate species. Nevertheless, emerging evidence suggests that population abundance and size‐at‐maturity declines of bycaught fish species correlate with increased fishing (Hedeholm et al, 2019; Jørgensen et al, 2014). Since conventional bottom trawl surveys are invasive and largely focused on areas of commercial interest, there is a need for less invasive monitoring tools of Greenlandic fish fauna across larger spatial scales, as species are shifting northwards (Christiansen et al, 2014).…”

Assessing the reproductive biology of the Greenland shark (Somniosus microcephalus)

“…Other Squaliforms: Data from 23 species were analyzed to identify trends of ovarian fecundity, uterine fecundity, size of ripe ova, body length-at-birth and/or reproductive strategy across the order ( S4 Table ). These species represent all seven families of Squaliforms as follows: Centrophoridae/Gulper sharks, N = 8 [ 21 , 23 , 29 – 37 ], Dalatiidae/Kitefin sharks, N = 1 [ 38 – 40 ], Echinorhinidae/Bramble sharks, N = 1 [ 41 , 42 ], Oxynotidae/Rough sharks, N = 2 [ 43 – 46 ], Etmopteridae/Lantern sharks, N = 4 [ 23 , 27 , 47 – 50 ], Somniosidae/Sleeper sharks, N = 4 [ 22 , 30 , 31 , 33 , 35 , 51 – 53 ], J. Guallart, unpublished data), and Squalidae/Dogfish sharks, N = 3 [ 54 – 64 ]. Although the extent of data sets varies between species and studies, we contend that such phylogenetic comparison allows for identifying general reproductive patterns among Squaliforms including Somniosidae to which the Greenland shark belongs.…”

“…Other Squaliforms: Data from 23 species were analyzed to identify trends of ovarian fecundity, uterine fecundity, size of ripe ova, body length-at-birth and/or reproductive strategy across the order (S4 Table). These species represent all seven families of Squaliforms as follows: Centrophoridae/Gulper sharks, N = 8 [21,23,[29][30][31][32][33][34][35][36][37], Dalatiidae/Kitefin sharks, N = 1 [38][39][40], Echinorhinidae/Bramble sharks, N = 1 [41,42], Oxynotidae/Rough sharks, N = 2 [43][44][45][46], Etmopteridae/Lantern sharks, N = 4 [23,27,[47][48][49][50], Somniosidae/Sleeper sharks, N = 4 [22,30,31,33,35,[51][52][53], J. Guallart, unpublished data), and Squalidae/Dogfish sharks, N = 3 [54][55][56][57][58][59][60][61][62][63][64]. Although the extent of data se...…”