Movements of lumpsucker females in a northern Norwegian fjord during the spawning season

Abstract

The lumpsucker Cyclopterus lumpus is distributed throughout the North Atlantic Ocean and migrates considerable distances between offshore feeding areas and shallow inshore spawning grounds. The number of the lumpsucker has declined since the mid 1980s, probably as a result of overexploitation. The lumpsucker is the preferred host of the sea louse Caligus elongates, which is a problem for marine aquaculture. However, little is known about the biology of the lumpsucker. The aims of the study were to 1) examine the movements of female lumpsucker during the spawning migration, and 2) assess the potential for lumpsucker to act as a vector for transmission of parasites and diseases between aquaculture farms and wild fish. Twenty female lumpsuckers tagged with acoustic transmitters were released during the spawning season in the inner part of Øksfjord, northern Norway and their distribution was recorded by 22 automatic acoustic receivers. The average time until departure from the fjord was 3 days, and within 1 week all fish had left the fjord. Timing of departure from the fjord was unrelated with either tidal current patterns or the time of the day. A high proportion of the fish (75%) were recorded within 200 m of fish farms, but they did not stay for extended periods at these farms. Our results suggest that mature female lumpsucker exhibit a movement pattern characterized by rapid fjord-scale migrations during the spawning season, and that they are not attracted to salmon farms in the same way as a range of other fish species.

The effect of temperature and fish size on growth of juvenile lumpfish (Cyclopterus lumpus L.)

“…They are often found mid-water as a frequent by-catch at 0-80 meters and occasionally feeding over abyssal waters up to 380 meters (Able & Irion 1985). Mitamura et al (2012) observed females migrating between neighboring fjords in search of spawning males, before residing for approximately 1-3 weeks to spawn. Lumpfish are active swimmers, often observed swimming against the current when performing migratory movements away from shore (Mitamura et al 2012), but can also exploit water currents facilitate rapid migrations to feeding grounds for lumpfish (Rusyaev 2013).…”

“…The migratory behavior of lumpfish is similar to that of coastal benthic teleosts, but adults are also frequently found mid-water in open oceans outside the spawning season (Cox & Anderson 1922;Andrijasev 1964;Myrseth 1971;Davenport & Kjorsvik 1986). As a semi-pelagic species, it spends most of its life at offshore feeding grounds at deep water before conducting an active migration over great distances towards shallow coastal waters to spawn between winter and early spring (Myrseth 1971;Blacker 1983;Davenport 1985;Goulet et al 1986;Holst 1993;Mitamura et al 2012). …”

“…It has been suggested that lumpfish return to spawn in the same area year after year (Thorsteinsson 1981;Mitamura et al 2012). Species with large north-south distributions such as juvenile turbot and Atlantic cod have been shown to display differences in terms of T opt SGR between latitudinal groups, indicating a genetic difference between populations which cannot be overcome during an acclimatization process (Imsland et al 2000;Pörtner et al 2001).…”

“…Each female produces approximately 80 000 -159 000 eggs per spawning season (Andrijasev 1964;Collins 1976;Daborn & Gregory 1983). The sex-ratio of lumpfish catches is imbalanced, Bañón et al (2008) found a 7 : 1 proportional balance favorable to female lumpfish, which is probably favorable to the spawning season as males are observed to take care of several batches at once (Mitamura et al 2012). Eggs in nests can be the results of one or several female spawnings, as males can mate with several females, and females likewise with several males.…”

“…They display similarities in migratory behavior to that of coastal benthic teleosts, but are also frequently found in mid-water in open oceans outside the spawning season (Davenport & Kjorsvik 1986). Lumpfish are semi-pelagic and will travel great distances to offshore feeding grounds, before returning to coastal spawning grounds between winter and early spring (Blacker 1983;Davenport 1985;Goulet et al 1986;Holst 1993;Mitamura et al 2012). They are often found mid-water as a frequent by-catch at 0-80 meters and occasionally feeding over abyssal waters up to 380 meters (Able & Irion 1985).…”