Age, size, and sexual maturity of channeled whelk (Busycotypus canaliculatus) in Buzzards Bay, Massachusetts Item Type article Authors Peemoeller, Bhae-Jin; Stevens, Bradley G. DOI 10.7755/FB.111.3.5 Download date 26/09/2021 13:40:14 Link to Item http://hdl.handle.net/1834/30371 265 Abstract—With the southern New Age, size, and sexual maturity of channeled England lobster fishery in distress, lobster fishermen have focused more whelk (Busycotypus canaliculatus) in effort toward harvesting channeled Buzzards Bay, Massachusetts whelk (Busycotypus canaliculatus). However, minimal research has been conducted on the life history and Bhae-Jin Peemoeller (contact author)1 growth rates of channeled whelk. Bradley G. Stevens2 Melongenid whelks generally grow slowly and mature late in life, a characteristic that can make them Email address for contact author: [email protected] vulnerable to overfishing as fish- ing pressure increases. We sampled 1 Department of Natural Sciences channeled whelk from Buzzards Bay, University of Maryland Eastern Shore Massachusetts, in August 2010 and Carver Hall in July 2011, studied their gonad Princess Anne, Maryland 21853 development by histology, and aged Present address for contact author: 5013 Smith Farm Road them by examining opercula. Males Virginia Beach, Virginia 23455 had a slower growth rate and a low- 2 Living Marine Resources Cooperative Science Center er maximum size than females. Male Department of Natural Sciences whelk reached 50% maturity (SM50) University of Maryland Eastern Shore at 115.5 mm shell length (SL) and at Carver Hall the age of 6.9 years. Female whelk Princess Anne, Maryland 21853 reached SM50 at 155.3 mm SL and at the age of 8.6 years. With a mini- mum size limit of 69.9 mm (2.75 in) in shell width, males entered the fishery at 7.5 years, a few months after SM50, but females entered the fishery at 6.3 years, approximately 2 The channeled whelk (Busycotypus (maximum distance across shell) for years before SM50. Increased fishing pressure combined with slow growth canaliculatus: Melongenidae) sup- channeled whelk in Nantucket Sound rates and the inability to reproduce ports a small but growing fi shery between 1978 and 1981. Bruce (2006) before being harvested can eas- in Massachusetts. Most fishing is reported a decrease in mean SL be- ily constrain the long-term viability conducted by lobstermen during the tween 1994 and 2004 for a related of the channeled whelk fishery in off-season (spring and fall) or when species, knobbed whelk (Busycon Massachusetts. the lobster fi shery is slow; therefore, carica), subject to a dredge fi shery in fi shing of this species typically is Delaware Bay. done on a part-time basis. However, Most whelk research has been channeled whelk landings in Mas- conducted on knobbed whelk, and sachusetts increased substantially minimal research has been done on after 2000, as the southern New channeled whelk (Avise et al., 2004; England lobster stock declined, and Bruce, 2006; Castagna and Kraeuter, reached 1400 metric tons in 2011 1994; Eversole et al., 2008; Kraeu- with a value of $6.2 million (Glenn ter et al., 1989; Power et al.2; Walk- and Wilcox1). In addition, exvessel er et al., 2005; Walker et al., 2007). prices have nearly doubled from 2007 Because of limited information on to 2011, increasing the incentive to growth rates and size at maturity, expand effort in this fi shery (Glenn managers do not know if the current and Wilcox1). Fishing pressure may minimum size limit of 69.9 mm (2.75 affect the average size of whelks be- in) in shell width (SW) is appropri- cause many fi shermen may focus on ate to ensure the reproduction and catching larger whelks (>160 mm longevity of channeled whelk in Mas- shell length [SL]). Davis and Sisson Manuscript submitted 25 September 2012. (1988) reported declines in popula- 2 Power, A. J., C. J. Sellers, and R. L. Walk- Manuscript accepted 28 May 2013. tion density and mean shell width doi 10.7755/FB.111.3.5 er. 2009. Growth and sexual maturity Fish. Bull. 111:265–278 (2013). of the knobbed whelk, Busycon carica 1 Glenn, R., and S. Wilcox. 2012. Profi le (Gmelin, 1791), from a commercially of the channeled whelk pot fi shery, 9 p. harvested population in coastal Georgia, The views and opinions expressed or Report to the Massachusetts Marine Ad- 24 p. Occasional Papers of the Univer- implied in this article are those of the visory Commission. Massachusetts Di- sity of Georgia Marine Extension Ser- author (or authors) and do not necesarily vision of Marine Fisheries, Invertebrate vice, vol. 4. Marine Extension Service, refl ect the position of the National Fisheries Program, 1213 Purchase St., Univ. Georgia, Shellfi sh Research Labo- Marine Fisheries Service, NOAA. New Bedford, MA 02740. ratory, Savannah, GA. 266 Fishery Bulletin 111(3) sachusetts and to sustain the fi shery for this species. whelk by embedding opercula in plastic resin and then The minimum size limit was established by the State sectioning them. For validation of aging, they used labo- of Massachusetts on the basis of the size of market ac- ratory-reared knobbed whelk and embedded the opercu- ceptability (Glenn and Wilcox1). With increased fi shing la of 3 knobbed whelk of 6+ years and 3 knobbed whelk pressure and limited biological information, channeled of 7+ years. Kraeuter et al. (1989) reported the average whelk can easily become overfi shed, especially if they ages of these knobbed whelk at 6.0 and 7.2 years, re- are not able to reproduce before they enter the fi shery. spectively. Another aging technique involves bleaching The channeled whelk ranges from Cape Cod, Mas- knobbed whelk opercula and counting annuli (Bruce et sachusetts, to Cape Canaveral, Florida (Edwards and al.3). In the opercula of older knobbed whelk, Power et Harasewych, 1988). Growth rate and size at maturity al.2 found a “bubbling effect,” from growth ring overlap, for channeled whelk are virtually unknown, but whelks due to decreased growth rates. of the family Melongenidae typically are slow growing, There are no published reports on the histological late maturing animals. In the seaside lagoons of Vir- staging of channeled or knobbed whelk gonads. We be- ginia, knobbed whelk reach a mean size of 176.1 mm gan this study to provide useful biological information, SL in 9–11 years (Kraeuter et al., 1989). In South Caro- such as size and age at sexual maturity, for managers of lina, knobbed whelk <90 mm SL grow faster than larger the channeled whelk fi shery in Massachusetts. Data on whelk (up to 7 times faster), although some knobbed the size at sexual maturity will provide managers with whelk have minimal or negative growth (Eversole et information needed to set minimum size limits that al- al., 2008). It has been suggested that channeled whelk low females to spawn at least once and, therefore, to have low fecundity because they lay egg strings only help prevent overfi shing (Gordon, 1994). We sampled once a year (Edwards and Harasewych, 1988). Betzer channeled whelk in Buzzards Bay, Massachusetts, and and Pilson (1974) reported an annual change in gonad expected that they would be protandrous hermaphro- index (fresh weight of the gonad/fresh weight of whole dites as reported for laboratory-reared knobbed whelk soft tissues) of channeled whelk in Narragansett Bay, by Castagna and Kraeuter (1994). We hypothesized that Rhode Island, with spawning most likely occurring in SL would increase with age and that slower growth late summer and fall. No studies have been published would occur at older ages. We provide the fi rst informa- that provide the spawning season of channeled whelk tion on the relationship between size, age, and stages or the environmental factors, such as temperature and of gonad development for channeled whelk and on the salinity, at which they spawn. In a study of this species size and age at 50% maturity (SM50) of male and female in aquaria, channeled whelk began hatching from an channeled whelk. egg string on 18–30 April 2010 at water temperatures of 15–18°C; the egg string was collected on 1 March 2010 near Cedar Island, Virginia (Harding, 2011). Materials and methods Channeled whelk may have a similar reproductive cycle to that of knobbed whelk. On intertidal fl ats in Sampling Virginia, knobbed whelk copulated in June and July and laid egg strings from mid-August to November; hatch- Sampling was conducted off Massachusetts in Buzzards ing occurred from mid-March to early May (Castagna Bay, a large, semi-enclosed estuary in the northeastern and Kraeuter, 1994). Knobbed whelk egg cases found in United States (Fig. 1). Buzzards Bay is uniformly shal- Cedar Island, Virginia, in 1977 yielded an average of low, with depths mostly at 10–15 m, and is open to 3770 whelk per string (Castagna and Kraeuter, 1994). the sea at multiple locations. As a result, the water However, information on the fecundity of channeled column in this bay is extremely well mixed, and differ- whelk is needed. The mode of reproduction for whelks ences between surface and bottom temperatures rare- also needs investigation because Castagna and Kraeu- ly exceed 1°C, and salinities are almost uniformly 30 ter (1994) suggested that knobbed whelk may be pro- ppt (Turner et al., 2009). Commercial wooden or wire tandrous hermaphrodites. Knobbed whelk raised in a mesh conch traps, baited with the Atlantic horseshoe laboratory were all males at 9 years, but, after 13 years, crab (Limulus polyphemus), were used to collect chan- some males changed sex, and at the age of 14 years, pro- neled whelk from Buzzards Bay in August 2010 and duced viable offspring (Castagna and Kraeuter, 1994).