Sustainability of Fisheries for Deep-water Cartilaginous Fishes Verónica B. García, Luis O. Lucifora and Ransom A. Myers Dalhousie University, Department of Biology, 1355 Oxford St., Halifax, NS, B3H 4J1, Canada

Introduction Results The global crisis of shallow fisheries resulted in a new interest for fishing in deep waters, increasing the impact of deep sea condrichthyans fishing activities on deep-water ecosystems.  C. monstrosa 150000 Reports of landings of 0.4 We analyzed trends in landings of deep-sea cartilaginous deep sea cartilaginous fishes 0.3 fishes since 1950 to 2002, and estimated productivity of 100000 are as early as 1950 and

deep-sea cartilaginous fishes for which information on life there is an increasing trend 0.2

history exists. Finally, we assessed sustainability of current 50000 since that year (Fig. 2). elasticity landings (TM) 0.1 fishing pressures taking the factor of landing increase as a However, species are often rough estimate of the increase in fishing mortality. 0 lumped into broad categories 0 1950 1960 1970 1980 1990 2000 eggs neonates juveniles subadults adults Stage-based matrix models were developed to estimate the year (e.g. Rajiformes, Squalidae). Fig. 2 rate of increase of four deep-sea sharks (Centrophorus  Since 1990, landings C. granulosus squamosus, C. granulosus, Centroscymnus coelolepis and 3500 0.6 reports became more Deania calcea), and one chimaera (Chimaera monstrosa). 3000 Chimaera monstrosa 0.5 Centrophorus granulosus 2500 accurate reporting some 0.4

Centrophorus squamosus species individually. Species 0.3 2000

Centroscymnus coelolepis specific landings increased elasticity 0.2 Material and Methods 1500 landings (TM)landings 0.1 Deania calcea by a factor of 53-1588, The stage based models were developed for each species in order 1000 to obtain an estimate of the rate of population increase (r). depending on the species 0 500 neonates juveniles adults According to the life history of every species the models’ stages and (Fig. 3). 0 their duration differed among species (Fig. 1). For every stage, the 1985 1989 1993 1997 2001 C. squamosus probability of surviving and growing into another stage, G, and the 0.4 Fig. 3 ye ar probability of surviving and remaining in a stage, P, were calculated 0.3 as: Gi = pi dj (1 - pi) / (1 - pi dj) and Pi = ((1 - pi dj-1)/(1 - pi dj)) pi  In general, without any Table 2. Population rates of increase of the five analyzed species of 0.2

deep sea chondrichthyans. elasticity where dj is stage duration in yr and pi is the stage-specific exploitation all species 0.1 survivorship values calculated from Jensen’s estimates of mortality studied have low productivity r without fishery r with fishery 0 as M = 1.65/age at maturity. In all cases, we considered the (r ranging from 0 to 0.05), neonates juveniles subadults adults mortality of neonates as double of the juveniles; the other stages except C. coelolepis and C. Centrophorus granulosus -0.08 -7.26 were considered to have the same mortality value. monstrosa, which have C. monstrosa Elasticity analyses were performed in order to identified the most Centroscymnus coelolepis 0.17 -0.75 0.4 sensitive stages. moderate productivity (r = The impact of fishing on each chondrichthyan species was 0.17) (Table 2). Chimaera monstrosa 0.17 -0.28 0.3 assessed by multiplying mortality by a factor obtained by dividing Deania calcea 0.05 -0.15 0.2 the maximum landing by the minimum landing larger than zero. This When mortality is changed elasticity factor was applied to the stages exposed to fishing: subadults and by the same factor as Centrophorus squamosus 0.04 -0.07 0.1 adults stages for all species, excepting C. granulosus in which landings increased, all fishing was applied to juveniles and adults. 0 species studied showed a  Elasticity analyses showed that the population eggs neonates juveniles subadults adults Life history parameters used in this study are presented in Table 1. negative rate of population dynamics of C. squamosus, D. calcea, and C. C. coelolepis increase. From the most to monstrosa is more sensitive to changes in the 0.3 Table 1. Life history parameters of the studied species the less impacted, species parameters of the juvenile stages and C. Age to Life span Litter size Reproductive Gestation Source maturity (years) periodicity length are ordered as follow: C. coelolepis and C. granulosus are more sensitive 0.2 (years) (years) (years) granulosus, C. coelolepis, C. to changes in the adult stages (Fig. 4). This is

Chimaera 11.71 28.88 22 1 1 1,2,3 elasticity monstrosa, D. calcea, and C. expectable given the lower age at maturity of the 0.1 monstrosa Centrophorus 44 70 8 1 1.5 4,5,6 squamosus (Table 2). latter two species. squamosus 0 neonates juveniles subadults small gestating large gestating resting small resting large Centroscymnus 5.52 15.30 6 2 1 4,7,8,9 Fig. 1 adults adults adults coelolepis 8.09 Centrophorus granulosus Deania calcea Centrophorus 12.2 25 1 1 2.5 10 F F Fig. 4 granulosus

G5 Deania calcea 25 35 13 4 1.83 6,11 gestating resting neonates juveniles subadults neonates juveniles adults adults adults 1 yr 9 yr 17.5 yr 1 yr 11.2 yr 12.8 yr G1 G2 G3 1.83 yr G4 2.17 yr G 1 G2 Conclusion 1- Moura, T., I. Figueiredo, P. Machado, & L. S. Gordo. 2004. Growth pattern and reproductive strategy of the holocephalan Chimaera monstrosa along the Portuguese continental slope. J. Mar. Biol. Ass. U.K. 84: 801- P P P3 P P5 804. 2 P3 2 4 Given the low values of r of the 2- Freer, D.W.L. & C.L. Griffiths. 1993. The fishery for, and general biology of, the St Joseph Callorhinchus capensis (Dumeril) off the South-Western Cape, South Africa. S. Afr. J. Mar. Sci. 13: 63-74. Centrophorus squamosus Chimaera monstrosa deep water cartilaginous fishes 3- Di Giacomo, E.E. & M.R. Perier. 1994. Reproductive biology of the cockfish, Callorhynchus callorhynchus F (Holocephali: Callorhynchidae), in Patagonian waters (Argentina). Fish. Bull. 92: 531-539. F studied here, the sustainability 4- Clarke, M.W., P.L. Connolly & J.J. Bracken. 2001. Aspects of reproduction of the deep water sharks Centroscymnus coelolepis and Centrophorus squamosus from west of Ireland and Scotland. J. Mar. Biol. of fisheries based on these adults Ass. U.K. 81: 1019-1029. neonates juveniles subadults adults eggs neonates juveniles subadults 17.17 yr species is possible with very 5- Clarke, M.W., P.L. Connolly & J.J. Bracken. 2002. Age estimation of the exploited deepwater shark 1 yr 21 yr 22 yr 26 yr 1 yr 1 yr 5.35 yr 5.35 yr G1 G2 G3 Centrophorus squamosus from the continental slopes of the Rockall Trough and Porcuspine Bank. J. Fish G1 G2 G3 G4 low fishing mortalities. Biol. 60: 501-514. 6- Clarke, M.W., C.J. Kelly, P.L. Connolly & J.P. Molloy. 2003. A life history approach to the assessment and management of deepwater fisheries in the Northeast Atlantic. J. Northw. Atl. Fish. Sci. 31:401-411. P3 P4 P5 P P 7- Figueiredo, I., L. Carvalho, M. Quaresma, & M. Clarke. 2002. First approach to the application of life table 2 3 P 4 models to Portuguese dogfish (Centroscymnus coelolepis, Bocage and Capello, 1984). NAFO SCR Doc. F4 F5 02/138. Centroscymnus coelolepis 8- Girard, M. & M.H. Du Buit. 1999. Reproductive biology of two deep-water sharks from the British Isles, G7 Centroscymnus coelolepis and Centrophorus squamosus (Chondrichthyes: Squalidae). J. Mar. Biol. Ass. small large resting resting U.K. 79: 923-931. G 9- Yano, K. & S. Tanaka. 1988. Size at maturity, reproductive cycle, fecundity, and depth segregation of the neonates juveniles subadults gestating gestating small 6 large 1 yr 2.25 2.25 adults adults adults adults G G G deep sea squaloid sharks Centroscymnus owstoni and C. coelolepis in Suruga Bay, Japan. Nippon Suisan 1 2 3 1yr 1 yr 1 yr 1 yr Gakkaishi 54(2): 167-174. 10- Guallart, J. 1998. Contribución al conocimiento de la biología y la taxonomía del tiburón batial Centrophorus granulosus (Bloch y Schneider, 1801) (Elasmobranchii, Squalidae) en el Mar Balear

(Mediterráneo occidental). PhD Thesis, Universitat de Valencia, 291 pp G4 G5 11- Clarke, M.W., P.L. Connolly & J.J. Bracken. 2002. Catch, discarding, age estimation, growth and maturity P2 P3 of the squalid shark Deania calceus west and north of Ireland. Fish. Res. 56: 139-153.