Estimating fishery effects in a marine protected area: Lamlash Bay

Abstract

Marine managers are looking increasingly to marine protected areas (MPAs) to deliver benefits to fisheries; however, many of these MPAs have been established in order to address specific conservation objectives unrelated to fisheries management. This paper describes a small no‐take zone (NTZ) set up in the Clyde, Scotland, for conservation purposes, and examines its effect on the abundance of two commercially fished scallops, Pecten maximus and Aequipecten opercularis, 5 years after closure. Scallop fishing immediately outside the NTZ has continued since this closure, although at lower intensities, with overall landings in the Clyde and landings per unit area rising until 2013, suggesting a slight increase in regional abundance. There was neither a significant increase in adult scallop abundance within the NTZ nor evidence of the dispersal of adults into surrounding areas. Transient dynamics and the small size of the NTZ may have played a role in the lack of demonstrable scallop recovery. The practice of ‘selling’ small conservation MPAs in terms of meeting wider fisheries objectives is discussed in light of this result.

Marine Conservation Begins at Home: How a Local Community and Protection of a Small Bay Sent Waves of Change Around the UK and Beyond

“…Despite signs that protection had increased the abundance of juvenile scallops, surveys up to 2014 did not find a significant effect of the NTZ on the density of adult scallops (Howarth et al, 2015b;Boulcott et al, 2018). This lack of an early response in adult scallop density could be due to several factors including:…”

“…(3) high variance of density estimates due to highly aggregated scallop distributions; and (4) episodic fluctuations in recruitment (Beukers- Stewart and Beukers-Stewart, 2009;Howarth et al, 2011Howarth et al, , 2015bBoulcott et al, 2018). Then again, both king scallop ages and sizes were significantly larger in the NTZ than outside (with differences increasing from 2010 to 2013), indicating that the population there was returning to a more natural, unfished state (Howarth et al, 2015b).…”

Ecological and Socio-Economic Effects of Highly Protected Marine Areas (HPMAs) in Temperate Waters

“…These effects result from the trade-off between recovery in the closed area and additional (displaced) fishing effects in the unprotected areas. If the threat to an area is overfishing of target species, this may thus be more effectively dealt with by specific measures to curb fishing effort rather than to establish HPMAs (Boulcott et al, 2018;Hilborn, 2018).…”

Scottish Inshore Fisheries Integrated Data System (SIFIDS): Work package (3) final report development of a novel, automated mechanism for the collection of scallop stock data

“…This can be advantageous when densities of target organisms are low. On the other hand, survey designs can be easier to implement using drop-down cameras because point-based randomised designs can be applied -see Boulcott et al (2018) for an example of such a scallop survey.…”

“…The present system was relatively cheap with a total construction cost in the region of £2000. However, the use of cheap cameras means that the present system is limited to a maximum operating depth of 50 m. Extending this range to greater depths would involve investment in more costly cameras, additional cabling and adding auxiliary illumination (Boulcott et al, 2018).…”