scholarly journals Noteworthy occurrences among six marine species documented with community engagement in the Canadian Arctic

2021 ◽  
Vol 8 (1) ◽  
pp. 74-83
Author(s):  
Darcy G. Mc Nicholl ◽  
Les N. Harris ◽  
Tracey Loewen ◽  
Peter May ◽  
Lilian Tran ◽  
...  

Abstract Arctic marine ecosystems are changing, one aspect of which appears to be distributional expansions of sub-arctic species. For Arctic marine systems, there is limited occurrence information for many species, especially those found in restricted habitats (e.g., ice-covered, far north, or deep-water). Increasing observations through on-going Fisheries and Oceans Canada (DFO) community-based monitoring programs (e.g., Arctic Coast, Cambridge Bay Arctic Char stock assessment, Arctic Salmon, and Kugluktuk coastal surveys), community observation networks, and local media have augmented opportunities to document new occurrences of marine fishes. Combined data from historical records and contemporary observations at the local scale can then delineate these among three types of occurrences: gradual distributional expansion, episodic vagrants, and rare endemics. Here we document nine occurrences of unusual sightings across six fish species (Pink Salmon Oncorhynchus gorbuscha, Bering Wolffish Anarhichas orientalis, Greenland Shark Somniosus microcephalus, Broad Whitefish Coregonus nasus, Banded Gunnel Pholis fasciata and Salmon Shark Lamna ditropis) from six northern Canadian communities and classify the nature of each observation as rare, vagrant, or expanding distributions. Uniting scientific and local observations represents a novel approach to monitor distributional changes suitable for a geographically large but sparsely populated area such as the Canadian Arctic. The new occurrences are important for discerning the potential effects of the presence of these species in Arctic ecosystems. These observations more broadly will build on our understanding of northern biodiversity change associated with warming Arctic environments.

Author(s):  
Yuan Yan ◽  
Eva Cantoni ◽  
Chris Field ◽  
Margaret A Treble ◽  
Joanna Mills Flemming

Excess bycatch of marine species during commercial fishing trips is a challenging problem in fishery management worldwide. The aims of this paper are twofold: to introduce methods and provide a practical guide for spatio-temporal modelling of bycatch data, as well as to apply these methods and present a thorough examination of Greenland shark bycatch weight in a Canadian Arctic fishery. We introduce the spatially explicit two-part model and offer a step by step guide for applying the model to any form of bycatch data, from data cleaning, exploratory data analysis, variable and model selection, model checking, to results interpretation. We address various problems encountered in decision making and suggest that researchers proceed cautiously and always keep in mind the aims of the analysis when fitting a spatio-temporal model. Results identified spatio-temporal hotspots and indicated month and gear type were key drivers of high bycatch. The importance of onboard observers in providing robust bycatch data was also evident. These findings will help to inform conservation strategies and management decisions, such as limiting access to spatial hotspots, seasonal closures and gear restrictions.


2013 ◽  
Vol 2013 ◽  
pp. 1-12
Author(s):  
Zhixiong Chen ◽  
Yi Ding ◽  
Rusty Laracuenti ◽  
Bernard Lipat

The contamination of the Pacific Ocean by the radioactive pollutants released from the Fukushima Daiichi Nuclear Power Plant has raised legitimate concerns over the viability of marine wildlife. We develop a modified Crank-Nicholson method to approximate a solution to the diffusion-advection-decay equation in time and three spatial dimensions to explore the extent of the effects of the radioactive effluent on two marine species: the Pacific Bluefin Tuna (Thunnus orientalis) and the Pacific Pink Salmon (Oncorhynchus gorbuscha).


2020 ◽  
pp. 11-41
Author(s):  
Guido di Prisco ◽  
Nicoletta Ademollo ◽  
Stefania Ancora ◽  
Jørgen S. Christiansen ◽  
Daniela Coppola ◽  
...  

1965 ◽  
Vol 22 (6) ◽  
pp. 1477-1489 ◽  
Author(s):  
H. T. Bilton ◽  
W. E. Ricker

Among 159 central British Columbia pink salmon that had been marked by removal of two fins as fry and had been recovered in commercial fisheries after one winter in the sea, the scales of about one-third showed a supplementary or "false" check near the centre of the scale, in addition to the single clear-cut annulus. This evidence from fish of known age confirms the prevailing opinion that such extra checks do not represent annuli, hence that the fish bearing them are in their second year of life rather than their third. Unmarked pink salmon from the same area, and some from southern British Columbia, had a generally similar incidence of supplementary checks. In both marked and unmarked fish the supplementary checks varied in distinctness from faint to quite clear. In a sample of scales of 14 double-fin marked chum salmon which were known to be in their 4th year, all fish had the expected 3 annuli, and 12 fish had a supplementary check inside the first annulus.


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