Growth of the harbour porpoise (&lt;i&gt;Phocoena phocoena&lt;/i&gt;) in eastern Newfoundland, Canada

Richardson, S F; Stenson, Garry B.; Hood, Christopher

doi:10.7557/3.2748

Cited by 6 publications

(5 citation statements)

References 30 publications

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“…The distribution of catch reports confirms that harbour porpoises are only present during the summer and fall months in waters around the island of Newfoundland (Richardson, 1992; Fig. 2).…”

Section: Estimated Small Cetacean Incidental Catch In 2001-03supporting

confidence: 67%

Recent harbour porpoise bycatch in gillnet fisheries in Newfoundland and Labrador, Canada

Benjamins¹,

Lawson²,

Stenson³

2023

JCRM

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Despite reduced fishing effort in many North Atlantic fisheries following collapse of fish stocks, concerns remain about levels of direct mortality of harbour porpoise (Phocoena phocoena), primarily through incidental catches in fishing gear. Although harbour porpoise incidental catch is known to occur in several fisheries along the coast of Newfoundland and Labrador, Canada, there are no reliable quantitative estimates for the last decade when the commercial fisheries have undergone major changes in effort and target species. Based on incidental catch rates derived using different reporting methods, with net-days as measures of effort and fishing trips as sampling units, the potential number of incidental catches of harbour porpoises in several gillnet fisheries in Newfoundland waters was estimated for the years 2001, 2002 and 2003. Confidence intervals were calculated using re-sampling techniques. Incidental catches of small cetaceans were estimated to be 862 in 2001, 1,428 in 2002 and 2,228 in 2003 in Newfoundland gillnet fisheries; virtually all cetaceans reported were harbour porpoises. Annual estimates of incidental catch of small cetaceans varied greatly between fisheries and areas. Confidence intervals were large due to variation in reported incidental catch rates among individual fishers and geographic areas. Most small cetaceans were reported in the nearshore cod fishery, although there were also numerous reports of catches in nearshore fisheries for lumpfish, herring and Greenland halibut. Incidental catch of small cetaceans was also identified in offshore fisheries for monkfish, white hake and Greenland halibut. Most incidental catch events occurred during the third quarter of the year (July-September) along the south coast, although catches of harbour porpoises were also reported during the second and fourth quarters. Several strategies could be implemented to better monitor small cetacean incidental catch in Newfoundland and Labrador waters. However, harbour porpoise population estimates are required before it can be determined if this fisheries-related mortality occurring in Newfoundland is sustainable.

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Section: Estimated Small Cetacean Incidental Catch In 2001-03supporting

confidence: 67%

Recent harbour porpoise bycatch in gillnet fisheries in Newfoundland and Labrador, Canada

Benjamins¹,

Lawson²,

Stenson³

2023

JCRM

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“…, Richardson et al . ). A single Gompertz growth curve was used in the current study, as asymptotic values obtained from this plot were thought to be sufficient for assessing if individuals had attained a stable adult size (after Murphy and Rogan ).…”

Section: Discussionmentioning

confidence: 97%

Life history of harbor porpoises (Phocoena phocoena) in Scottish (UK) waters

Learmonth

Murphy

Luque

et al. 2014

Marine Mammal Science

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Life history parameters were determined for stranded and bycaught harbor porpoises (Phocoena phocoena) from Scottish (UK) waters (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005). Fetal growth rate was 84.4 mm/mo and mean size at birth was 76.4 cm (range 65-88 cm). Males and females had a similar range of body lengths (65-170 cm and 66-173 cm, respectively), although asymptotic lengths were higher in females than males (approximately 158 cm and 147 cm, respectively). Nonpregnant females were significantly lighter, in relation to their length than males. Maximum estimated age was 20 yr for both sexes. Age at sexual maturity (ASM) was estimated as 4.35 yr in females and 5.

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“…Information on vital parameters are available from a number of regions including the Gulf of Maine/ Bay of Fundy (Fisher and Harrison 1970, Read and Gaskin 1990, Read and Hohn 1995, Newfoundland (Richardson 1992, Richardson et al 2003, Greenland (Kinze et al MS 1990, Norway (Bjørge et al 1991), Denmark (Møhl-Hansen 1954, Clausen and Andersen 1988, Sorensen and Kinze 1994, Lockyer and Kinze 2003, Germany (Benke et al 1998), The Netherlands (Addink et al 1995), Ireland (Rogan and Berrow 1995), United Kingdom (Lockyer 1995a), Spain (Lens 1997), Portugal (Sequeira 1996), andWest Africa (Smeenk et al 1992). The available data on population parameters of harbour porpoise in the North Atlantic are reviewed by Lockyer (2003).…”

Section: Biological Parametersmentioning

confidence: 99%

“…Many studies have found that these samples are biased towards younger animals and/or unequal sex ratios (e.g. IWC 1991, Richardson et al 2003, Sørensen and Kinze 1994, Lockyer 1995b). Such samples can provide an indication of vital parameters that can be used as a starting point or for comparisons between samples, but caution must be used as they may exhibit unknown biases that could affect the estimates of the age structure, sex ratios and/or reproductive status of the population (Donovan and Bjørge 1995).…”

Section: Biological Parametersmentioning

confidence: 99%

“…The available estimates of harbour porpoise abundance were reviewed by the IWC in 1995 (Donovan and Bjørge 1995). They presented estimates for all or part of a number of sub-populations including Gulf of Maine/Bay of Fundy (1991,1992), Iceland (1987), North Norway/Barents Sea (1989), Kattegat and adjacent waters (1992), North Sea (1989, 1991 and Ireland and western UK (1994) ( Table 1). New or updated estimates are now available for areas including the Gulf of Maine/Bay of Fundy, Gulf of St. Lawrence, North Sea and Baltic (Table 1).…”

Section: Abundancementioning

confidence: 99%

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Harbour porpoise (<i>Phocoena phocoena</i>) in the North Atlantic: Abundance, removals, and sustainability of removals

Stenson

2003

NAMMCOSP

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The status of harbour porpoise (Phocoena phocoena) populations in the North Atlantic has raised numerous concerns. Although a number of factors that may be adversely affecting harbour porpoise populations have been identified, focus has been on the impact of removals, primarily due to incidental catches in fishing gear. As a result, considerable efforts have been made to determine the levels and/or impact of bycatch in a number of areas. Unfortunately, many areas remain little studied. Currently, harbour porpoise are listed as threatened or vulnerable in many parts of their range. In order to determine if the current levels of removals are sustainable, information on stock identity and seasonal movements, population parameters, abundance, and the magnitude of removals is required. Although substantial progress has been made to improve our knowledge of these parameters in the last decade, significant gaps still exist. After reviewing the available data for each sub-population in the North Atlantic, it is clear that the information required to assess the status of harbour porpoise populations is still not available for most areas. Attempts have been made to assess the status of harbour porpoise based on trends in sightings or, in areas where information on abundance and bycatch are available, on models using arbitrary criteria and/or theoretical estimates of potential population growth. Detailed case-specific population models have been proposed but are not yet available.

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Growth of the harbour porpoise (<i>Phocoena phocoena</i>) in eastern Newfoundland, Canada

Cited by 6 publications

References 30 publications

Recent harbour porpoise bycatch in gillnet fisheries in Newfoundland and Labrador, Canada

Recent harbour porpoise bycatch in gillnet fisheries in Newfoundland and Labrador, Canada

Life history of harbor porpoises (Phocoena phocoena) in Scottish (UK) waters

Harbour porpoise (<i>Phocoena phocoena</i>) in the North Atlantic: Abundance, removals, and sustainability of removals

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