Distribution, population dynamics and growth rates of Thysanopoda acutifrons, Thysanoessa inermis and Nematobrachion boopis in the Irminger Sea, North Atlantic

作者：Saunders R A^*; Rasmussen J; Tarling G A; Brierley A S

来源：Journal of the Marine Biological Association of the United Kingdom, 2013, 93(5): 1287-1301.

DOI：10.1017/S0025315412001385

• euphausiids
• body growth rates
• population dynamics
• Irminger Sea
• North Atlantic

Euphausiids are an important component of the northern North Atlantic ecosystem and several species are found in the Irminger Sea. However, data on euphausiids in this region are few, particularly for Thysanopoda acutifrons, Thysanoessa inermis and Nematobranchion boopis. In this paper, we present the first data since the 1930s on the seasonal distribution and population dynamics of these species from net haul data collected in the Irminger Sea during winter, spring and summer 2001-2002. Thysanoessa inermis was the most numerically abundant (0.63-26.62 ind. 1000 m(-3)) of the three species in the region and comprised a biomass of 3.92-41.74 mg 1000 m(-3). The species was largely found in the upper regions of the water column (0-400 m) and was distributed in the more on-shelf/shelf-break regions around East Greenland and Iceland. Growth rates were around 0.03 mm d(-1) for T. inermis and there was some evidence that either the timing of spawning was delayed, or larval development was prolonged in the region. Thysanopoda acutifrons was predominantly distributed below 400 m in more oceanic regions and had a low abundance (1.23-1.64 ind. 1000 m(-3)) throughout the Irminger Sea. However, the species comprised a relatively high proportion of biomass (19.39-31.33 mg 1000 m(-3)) due to its large body size. Our data showed that the species had low rates of growth (0.04 mm d(-1)) and development throughout the year, and that the reproductive season occurred during the overwintering period (November/December) once individuals had reached two years of age. Nematobranchion boopis mainly occurred below 400 m at low abundance (0.06-0.18 ind. 1000 m(-3)) levels throughout the region. The species was largely found where Atlantic waters prevailed in the Irminger Current and its growth rates were variable (0.02-0.06 mm d(-1)). Nematobranchion boopis was a year-round spawner and the species had fairly rapid rates of post-larval development, with the newly spawned 0-group reaching sexual maturity within the first 6 months. Data presented in this paper provide useful baselines for understanding the possible impacts of long-term, broad-scale environmental change on the ecology of euphausiid communities in the Irminger Sea.

• 出版日期2013-8
• 单位British Antarctic Survey