Reproductive Biology and Fishery-Related Characteristics of the Malabar Grouper (Epinephelus malabaricus) Caught in the Coastal Waters of Mafia Island, Tanzania
The reproductive biology and fishery-related characteristics of the Malabar grouper (Epinephelus malabaricus) (Bloch and Schneider, 1801) specimens were investigated. The size of females ranged from 25 to 113？cm total length ( ), with 50% sexually mature at 79？cm , and the males (97？cm to 114？cm ) were larger than the females. Due to the sex ratios and size distribution of the sample, it appeared that the groupers change sex between 97 and 113？cm . However, the gonadal histology data lacked specimens in the transitional stage. The spawning peak occurred in November, as defined by the presence of ripe females, and the spawning season lasted from September to February. The size of the fish correlated positively with the water depth at capture, which is also related to oxygen levels in deep water being more favourable for larger fish. Larger specimens (>100？cm ) were targeted by fishers between December and February, when the northeast monsoon coincides with calmer weather and the spawning season. Fishers were interviewed, and observations were made on fishing gear, vessels, and grounds. There was no indication that small-scale fishers targeted spawning aggregations; therefore, fisheries independent research is recommended in order to verify the time, location, and behaviour of the spawning of Malabar groupers for management and conservation purposes. 1. Introduction The population size structure, mode of reproduction, maturity, and fisheries characteristics (fishing gear, vessels, and fishing grounds) of various Epinephelinae are well documented in the Western Atlantic, the Caribbean, Southeast Asia, and Australian waters [1–4]. In contrast, virtually no such data is available for the same species in Tanzanian waters, despite their frequent presence in local fish markets (pers. observations). Being highly priced fish, the Epinephelinae are heavily exploited in many tropical areas of the world for commercial purposes, aquaculture ventures (e.g., Epinephelus malabaricus and Epinephelus coioides) and for recreational and local consumption [4–6]. The increasing exploitation is attributed to growing markets, especially worldwide export markets for the fish [7, 8]. Groupers have long lifespans, are slow growing, relatively large in size, and have a low natural mortality rate. The larger species form breeding aggregations, and most species are protogynous hermaphrodites. Among the Epinephelinae, monandry protogynous hermaphroditism is the most common sexual pattern [9]. A few species, such as the Epinephelus coioides and the Epinephelus andersoni, are diandry,
References
[1]
M. A. J. Moe, “Biology of the red grouper Epinephelus morio (Valenciennes) from the eastern Gulf of Mexico,” Professional Paper 10, Florida Department of Natural Resources. Marine Research Laboratories, St. Petersburg, Fla, USA, 1969.
[2]
R. Thompson and J. L. Munro, “Aspects of the biology and ecology of Caribbean reef fishes: serranidae (hinds and groupers),” Journal of Fish Biology, vol. 12, no. 2, pp. 115–146, 1978.
[3]
M. C. Mackie, “Reproductive biology of the halfmoon grouper, Epinephelus rivulatus, at Ningaloo Reef, Western Australia,” Environmental Biology of Fishes, vol. 57, no. 4, pp. 363–376, 2000.
[4]
Y. Sadovy de Mitcheson, M. T. Craig, A. A. Bertoncini et al., “Fishing groupers towards extinction: a global assessment of threats and extinction risks in a billion dollar fishery,” Fish and Fisheries, vol. 14, no. 2, pp. 119–136, 2012.
[5]
P. C. Heemstra and J. E. Randall, FAO Species Catalogue. Groupers of the World (Family Serranidae, Subfamily Epinephelinae). An Annotated and Illustrated Catalogue of the Grouper, Rock Cod, Hind, Coral Grouper and Lyretail Species Known to Date, vol. 16, No. 125, FAO Fisheries Synopsis, Rome, Italy, 1993.
[6]
R. Yashiro, “Status of grouper breeding and culture in Thailand,” http://library.enaca.org/Grouper/Research/Breeding/2000/0803.htm#_ftn1, 1999.
[7]
Y. J. Sadovy, T. J. Donaldson, T. R. Graham et al., The Live Reef Food Fish Trade While Stocks Last, Asian Development Bank, Manila, Philippines, 2003.
[8]
Y. Sadovy and M. Domeier, “Are aggregation-fisheries sustainable? Reef fish fisheries as a case study,” Coral Reefs, vol. 24, no. 2, pp. 254–262, 2005.
[9]
D. Y. Shapiro, “Reproduction in groupers,” in Tropical Snappers and Groupers: Biology and Fisheries Management, J. J. Polovina and S. Ralston, Eds., pp. 295–327, Westview Press, London, UK, 1987.
[10]
Y. Sadovy and D. Y. Shapiro, “Criteria for the Diagnosis of Hermaphroditism in Fishes,” in Copeia, pp. 136–156, 1987.
[11]
S. T. Fennessy and Y. Sadovy, “Reproductive biology of a diandric protogynous hermaphrodite, the serranid Epinephelus andersoni,” Marine and Freshwater Research, vol. 53, no. 2, pp. 147–158, 2002.
[12]
E. M. Grandcourt, T. Z. Al Abdessalaam, F. Francis, A. T. Al Shamsi, and S. A. Hartmann, “Reproductive biology and implications for management of the orange-spotted grouper Epinephelus coioides in the southern Arabian Gulf,” Journal of Fish Biology, vol. 74, no. 4, pp. 820–841, 2009.
[13]
S. Bannerot, W. W. Fox Jr., and J. E. Powers, “Reproductive strategies and the management of snappers and groupers in the Gulf of Mexico and Caribbean,” in Tropical Snappers and Groupers: Biology and Fisheries Management, J. J. Polovina and S. Ralston, Eds., pp. 561–603, Westview Press, London, UK, 1987.
[14]
G. R. Huntsman, J. Potts, R. W. Mays, and D. Vaughan, “Groupers (Serranidae, Epinephelinae): endangered apex predators of reef communities,” in Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals. Symposium 23, J. A. Musick, Ed., pp. 217–231, American Fisheries Society, Washington, DC, USA, 1999.
[15]
A. V. Morris, C. M. Roberts, and J. P. Hawkins, “The threatened status of groupers (Epinephelinae),” Biodiversity and Conservation, vol. 9, no. 7, pp. 919–942, 2000.
[16]
A. Cornish and Grouper and Wrasse Specialist Group, “Epinephelus malabaricus,” in IUCN, 2012. IUCN Red List of Threatened Species. Version 2012. 1, 2006, http://www.iucnredlist.org/details/61338/0.
[17]
M. B. Pember, S. J. Newman, S. A. Hesp et al., “Biological parameters for managing the fisheries for Blue and King Threadfins, Estuary Rockcod, Malabar Grouper and Mangrove Jack in north-western Australia,” http://www.cffr.murdoch.edu.au/frdc/FRDC_2002-003.pdf, 2005.
[18]
M. T. Craig, Y. J. Sadovy de Mitcheson, and P. C. Heemstra, Groupers of the World: A Field and Market Guide, NISC (Pty) Ltd., Grahamstown, South Africa, 2011.
[19]
S. M. Garcia, J. Kolding, J. Rice et al., “Reconsidering the consequences of selective fisheries,” Science, vol. 335, no. 6072, pp. 1045–1047, 2012.
[20]
T. R. McClanahan, E. Verheij, and J. Maina, “Comparing the management effectiveness of a marine park and a multiple-use collaborative fisheries management area in East Africa,” Aquatic Conservation, vol. 16, no. 2, pp. 147–165, 2006.
[21]
B. Kaunda-Arara, G. A. Rose, M. S. Muchiri, and R. Kaka, “Long-term trends in coral reef fish yields and exploitation rates of commercial species from coastal Kenya,” Western Indian Ocean Journal of Marine Science, vol. 2, no. 2, pp. 105–116, 2003.
[22]
Y. J. Sadovy and A. C. J. Vincent, “Ecological issues and the trades in live reef fishes,” in Coral Reef Fishes. Dynamics and Diversity in a Complex Ecosystem, P. F. Sale, Ed., pp. 391–420, Academic Press, San Diego, Calif, USA, 2002.
[23]
I. Bryceson, N. Jiddawi, A. Kamukuru et al., “Fisheries study in Tanzanian coastal waters: the effects of trial export of finfish from Mafia Island on ecological-social resilience and vulnerability,” Report, Ministry of Natural Resources and Tourism and Norwegian Embassy, Tanzania, 2006.
[24]
T. R. McClanahan, “Seasonality in East Africa's coastal waters,” Marine Ecology Progress Series, vol. 44, pp. 191–199, 1988.
[25]
K. C. Garpe and M. C. ？hman, “Coral and fish distribution patterns in Mafia Island Marine Park, Tanzania: fish-habitat interactions,” Hydrobiologia, vol. 498, pp. 191–211, 2003.
[26]
I. Bryceson, “Seasonality of oceanographic conditions and phytoplankton in Dar es Salaam waters,” University Science Journal, vol. 8, no. 1, pp. 66–76, 1982.
[27]
“Length-based methods in fisheries research,” in Proceeding of the ICLARM Conference, D. Pauly and G. R. Morgan, Eds., vol. 13, International Center for Living Aquatic Resources Management; Kuwait Institute for Scientific Research, Safat, Kuwait, 1987.
[28]
C. L. Smith, “The patterns of sexuality and the classification of serranid fishes,” American Museum Novitates 2207, 1965, http://hdl.handle.net/2246/5399.
[29]
G. West, “Methods of assessing ovarian development in fishes: a review,” Australian Journal of Marine & Freshwater Research, vol. 41, no. 2, pp. 199–222, 1990.
[30]
B. P. Ferreira, “Reproduction of the common coral trout Plectropomus leopardus (Serranidae: Epinephelinae) from the central and northern Great Barrier Reef, Australia,” Bulletin of Marine Science, vol. 56, no. 2, pp. 653–669, 1995.
[31]
M. A. Samoilys and A. Roelofs, “Defining the reproductive biology of a large serranid, Plectropomus leopardus,” Technical Report 31, CRC Reef Research Centre Ltd., Townsville, Australia, 2000.
[32]
K. Rhodes and Y. Sadovy, “Temporal and spatial trends in spawning aggregations of camouflage grouper, Epinephelus polyphekadion, in Pohnpei, Micronesia,” Environmental Biology of Fishes, vol. 63, no. 1, pp. 27–39, 2002.
[33]
R. A. Wallace and K. Selman, “Cellular and dynamic aspects of Oocyte growth in Teleosts,” Integrative and Comparative Biology, vol. 21, no. 2, pp. 325–343, 1981.
[34]
D. Y. Shapiro, “Sex reversal and sociodemographic processes in coral reef fishes,” in Fish Reproduction: Strategies and Tactics, G. W. Potts and R. J. Wootton, Eds., pp. 113–118, Academic Press, London, UK, 1984.
[35]
M. Kulbicki, N. Guillemot, and M. Amand, “A general approach to length-weight relationships for New Caledonian lagoon fishes,” Cybium, vol. 29, no. 3, pp. 235–252, 2005.
[36]
R. R. Warner, “Mating behavior and hermaphroditism in coral reef fishes,” American Scientist, vol. 72, no. 2, pp. 128–136, 1984.
[37]
R. R. Warner, D. R. Robertson, and E. G. Leigh Jr., “Sex change and sexual selection,” Science, vol. 190, no. 4215, pp. 633–638, 1975.
[38]
R. J. Pears, J. H. Choat, B. D. Mapstone, and G. A. Begg, “Demography of a large grouper, Epinephelus fuscoguttatus, from Australia's Great Barrier Reef: implications for fishery management,” Marine Ecology Progress Series, vol. 307, pp. 259–272, 2006.
[39]
J. E. Randall, “A preliminary synopsis of the groupers (Perciformes: Serranidae: Epinephelinae) of the Indo-Pacific region,” in Tropical Snappers and Groupers: Biology and Fisheries Management, J. J. Polovina and S. Ralston, Eds., pp. 89–188, Westview Press, London, UK, 1987.
[40]
J. M. Leis, “Review of the early life history of tropical groupers (Serranidae) and snappers (Lutjanidae),” in Tropical Snappers and Groupers: Biology and Fisheries Management, J. J. Polovina and S. Ralston, Eds., pp. 189–237, Westview Press, London, UK, 1987.
[41]
D. Pauly, Gasping Fish and Panting Squids: Oxygen, Temperature and the Growth of Water-Breathing Animals, International Ecology Institute, Oldendorf, Germany, 2010.
[42]
M. Sheaves, “Large lutjanid and serranid fishes in tropical estuaries: are they adults or juveniles?” Marine Ecology Progress Series, vol. 129, no. 1-3, pp. 31–40, 1995.
[43]
M. Liu and Y. Sadovy, “Early gonadal development and primary males in the protogynous epinepheline, Cephalopholis boenak,” Journal of Fish Biology, vol. 65, no. 4, pp. 987–1002, 2004.
[44]
Y. J. Sadovy, “Reproduction of reef fishery species,” in Reef Fisheries-Fish and Fisheries Series 20, N. V. C. Polunin and C. M. Roberts, Eds., pp. 15–59, Chapman and Hall, London, UK, 1996.
[45]
M. A. Samoilys, J. Church, B. Kaunda-Arara, A. Kamukuru, and N. Jiddawi, “Preliminary findings on spawning aggregations of reef fishes in East Africa,” in Proceedings of the 10th International Coral Reef Symposium, pp. 1335–1346, 2006, http://www.reefbase.org/download/download.aspx?type=10&docid=12479.
