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Chapter 9 - Large Pelagic Fish© Maria Honig, Marine PhotobankNorth Atlantic albacore are presumed to spawn in theSargasso Sea and surrounding waters during the borealsummer and their larvae live in the upper 100 m of waterat a temperature range of 15 to 20 o C (Pusineri et al.2005). Juvenile fish range from 40 to 90 cm long and areconstrained to the same range and temperature. Albacorebecome sexually mature when they reach 90 cm in lengthand an age of about 5 years (Collette and Nauan 1983).Maximum reported age is 12 years and albacore can reacha maximum fork length of 140 cm and weight of 60.3kg. Like bluefin tuna, albacore are opportunistic feeders.Their main prey is fish (60% of biomass) and cephalopods(39%) (Pusineri et al. 2005). Studies of feeding behaviorin the central Mediterranean Sea have shown preferenceto other pelagic species like medium sized fish, cephalopods,and crustaceans (Consoli et al. 2008; Dragovich1969).Swordfish (Xiphias gladius)Swordfish range throughout the tropical, temperate, andcold-water areas (Collette and Klein-MacPhee 2002).Adult swordfish are found in coastal waters, but are primarilyoceanic and concentrations are seen between watermasses associated with boundary currents like the GulfStream (Govoni et al. 2003). Swordfish are found in theupper layers of the ocean, but feed throughout the watercolumn. This population is genetically different from thatfound in the Mediterranean Sea, and mixes only slightlywith the Mediterranean population west of Gibraltar andsouth of the NW African coast (Bremer et al. 2005a,b). Atlantic swordfish have two distinct populations,North Atlantic and South Atlantic, as demonstratedby mitochondrial and nuclear DNA studies (Bremer etal. 2005a). They annually migratethousands of miles along the easternseaboard of the United States andCanada, moving toward temperate orcolder waters during the summer forfeeding and back to warmer watersin fall for spawning and overwintering(HMS FMP 2002). In swordfish,the brain and eyes are warmer thanthe water in which they live, whichprotects the species on deep foragingdives (Collette and Klein-MacPhee2002).In the Northwest Atlantic, swordfishsegregate by size and sex; the largerindividuals, primarily females, canbe found in colder, higher-latitudewaters, but the females, along with the males, are eventuallyfound in the warmer breeding areas (Palko et al.1981). Spawning occurs throughout the year in severalwarm-water locations (e.g. south of the Sargasso Sea/upperCaribbean Sea, Southeast coast of United States)(Collette and Klein-MacPhee 2002). Larvae are mostoften found at temperatures greater than 24 o C and areoften found in nursery areas in the Gulf of Mexico andFlorida (NMFS 2009). These regions to the south of theNorthwest Atlantic may also serve as juvenile fish nurseryareas (NMFS 2009). Swordfish are opportunistic feeders,eating at different depths and at different trophic levelsduring the diurnal vertical migration (Stillwell and Kohler1985). The main prey items in the Northwest Atlanticregion are predominantly squid, followed by gadids, scombrids,butterfish, bluefish, and sand lance (Stillwell andKohler 1985).9-30Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report