Testing assumptions about sex change and spatial management in the protogynous gag grouper, Mycteroperca microlepis

2020 ◽  
Vol 639 ◽  
pp. 199-214
Author(s):  
S Lowerre-Barbieri ◽  
H Menendez ◽  
J Bickford ◽  
TS Switzer ◽  
L Barbieri ◽  
...  
Keyword(s):  
Deep Water ◽  
Marine Protected Area ◽  
Sex Change ◽  
Small Fish ◽  
Spawning Grounds ◽  
Large Spatial Scale ◽  
Spawning Aggregations ◽  
Spatial Management ◽  
Gag Grouper ◽  
Mycteroperca Microlepis

Gag grouper Mycteroperca microlepis are protogynous hermaphrodites, for which the assumption of female-driven reproductive potential may be inaccurate. In protogynous species, male abundance, fertilization success, and stock productivity are affected by where and when sex change occurs and how fishing pressure affects male recruitment and survivorship. In this study, we integrated large spatial-scale data with high-resolution data from a 3 yr study sampling gag at deep-water sites with varying spatial management (a marine protected area [MPA], a seasonally closed area, and an 'Open area'). Gag exhibited complex spatial ecology; females formed pre-spawning aggregations before migrating to deep-water spawning sites, which overlapped with locations where males were sampled year-round. The observed male sex ratio in the MPA was 5% compared to the expected 15%. It was 0% in less protected areas. Sex change occurred occasionally in small fish and before, during, and after the spawning season. In addition, sex change was observed in pre-spawning female-only aggregations as well on the spawning grounds, indicating that male social cues are not requisite. We propose that shallow-water, pre-spawning aggregations are a key spatio-temporal bottleneck to gag productivity. They appear to be an important source of transitionals and are heavily fished, which may negatively impact male recruitment to the spawning grounds. Our results indicate that overall gag abundance is low, MPAs do not protect all recruiting males (as previously assumed), and current regulations are not sufficient for the male population to recover to historic levels (~17% male).

Larval Connectivity and Marine Protected Area Networks

2020 ◽  
pp. 408-436
Author(s):  
Per-Olav Moksnes ◽  
Per R. Jonsson
Keyword(s):  
Protected Areas ◽  
Human Activities ◽  
Protected Area ◽  
Larval Dispersal ◽  
Marine Protected Area ◽  
Model Organisms ◽  
Ecosystem Resilience ◽  
Important Method ◽  
Larval Connectivity ◽  
Spatial Management

There is growing awareness that ocean life is under unprecedented stress caused by the loss of habitat and biodiversity resulting from human activities. Spatial management by establishing marine protected areas (MPAs) is proposed as an important method to conserve biodiversity, manage fisheries, and increase ecosystem resilience. However, a major challenge in spatial management is that most MPAs and networks of MPAs have been created with little regard to larval dispersal and connectivity within and outside protected areas. Because of the limited understanding of larval connectivity, it is therefore often unclear whether the MPAs are ecologically functional. Larval behavior and dispersal are particularly well studied in benthic crustaceans, making them excellent model organisms to address this challenge.

scholarly journals Limited mid-water scavenging of trawl discards

2003 ◽  
Vol 83 (4) ◽  
pp. 731-734 ◽  
Author(s):  
Karim Erzini ◽  
Pedro Monteiro ◽  
Artur Araújo ◽  
Margarida Castro
Keyword(s):  
Water Column ◽  
Deep Water ◽  
Small Fish ◽  
Sea Birds ◽  
Trawl Fishing ◽  
Southern Portugal ◽  
Catch Rates ◽  
Electric Fishing ◽  
Scavenging Rates

The consumption or scavenging of fish in the water column at depths from 75 to 275 m in Algarve (southern Portugal) trawl fishing grounds was evaluated. Longlines were used to suspend baits throughout the water column while electric fishing reels were used to simulate sinking discards. Eighteen species were caught, with higher catch rates near the surface than near the bottom. However, scavenging rates were generally highest near the bottom and lowest in the middle of the water column. At depths less than 100 m the majority or all the fish were scavenged throughout the water column, while at depths greater than 200 m most of the fish were untouched after periods of time greater than would be required for them to sink to the bottom. Since other studies have shown that most small fish discards are scavenged at the surface by sea birds and most of the discarded species that sink are either too large or not attractive to pelagic predators, these results suggest that mid-water scavenging of trawl discards in deep water is relatively unimportant.

Rock lobster movement patterns and population structure within a Tasmanian Marine Protected Area inform fishery and conservation management

2009 ◽  
Vol 60 (5) ◽  
pp. 417 ◽  
Author(s):  
Neville Barrett ◽  
Colin Buxton ◽  
Caleb Gardner
Keyword(s):  
Marine Protected Areas ◽  
Marine Protected Area ◽  
Conservation Management ◽  
Movement Patterns ◽  
Fold Increase ◽  
Reference Sites ◽  
Rock Lobster ◽  
Spatial Management ◽  
Ecosystem Interactions ◽  
Annual Time

As reference sites to better understand characteristics such as movement patterns, depletion of natural resources and ecosystem interactions, Marine Protected Areas (MPAs) are crucial in fishery and conservation management. The southern rock lobster (Jasus edwardsii) is an important reef predator in temperate Australasia and subject to heavy exploitation. In a Tasmanian MPA, 90% of individuals were recaptured less than 200 m from the point of release over weekly to annual time scales, regardless of size or sex. This lack of movement resulted in a substantial build-up of biomass and of large mature individuals in the MPA relative to adjacent fished locations. Although there was little spillover of individuals to the fishery, a 4-fold increase in female fecundity potentially enhanced larval export. Comparison of fished and unfished biomass of legal-sized animals suggested that exploitation had reduced biomass in the adjacent fishery to <10% of natural values. Overall, the demographic and movement patterns illustrate the extent of depletion of stocks in the absence of historical baseline data and the potential need for spatial management resulting from limited movement. Our data indicate that within MPAs, this predator can potentially recover in abundance to natural levels despite adjacent fishing pressure.

Creating Multi-Sectoral Ocean Industry Leadership in Marine Spatial Management

2009 ◽  
Author(s):  
Paul F. Holthus
Keyword(s):  
Biological Diversity ◽  
Oil And Gas ◽  
Marine Protected Area ◽  
Business Community ◽  
Offshore Wind ◽  
Convention On Biological Diversity ◽  
Spatial Management ◽  
Industry Leadership ◽  
Multi Stakeholder ◽  
Ocean Zoning

Marine spatial management is emerging as a key tool for managing and conserving marine ecosystems. The development and implementation of ocean zoning, especially Marine Protected Area (MPA) networks, is expanding rapidly around the world. At a global scale, ocean zoning and MPAs are being pursued in many processes through a variety of governmental, inter-governmental (e.g. UN agencies, regional bodies), with significant input from non-governmental organizations (NGOs). Ocean industries, e.g. oil and gas, shipping, fisheries, aquaculture, etc. are the principle user group affected by ocean zoning. Important new ocean uses are under development as well, e.g. offshore wind, ocean energy, carbon sequestration. The creation of ocean zones, such as MPA networks, will have major effects on industry access to marine space and resources, with significant implications for exploration, development, production and transport. It is essential that the industry constructively engage with marine spatial management efforts and stakeholders to ensure that the process is well informed and balanced. This will increase the potential for industry to respect the management regulations of ocean areas often far removed from the reach of governments. Unfortunately, industry is often not present at key ocean zoning developments, especially at the international level, and is not engaged in a constructive, coordinated manner that brings together the range of industries operating in the marine environment. Barriers to industry involvement in marine spatial management include: 1) Lack of understanding of the movement and momentum behind ocean zoning efforts; 2) Limited engagement in the multi-stakeholder processes where zoning is moving most rapidly, e.g. Convention on Biological Diversity, because industry is engaged in sectoral processes; 3) Lack of means for engaging the broader ocean business community on marine management and sustainability issues, particularly at a global level. This paper will outline the need, opportunity and progress in creating proactive, constructive industry leadership and collaboration on ocean zoning, including: 1) Developing an understanding of marine spatial management issues, stakeholders and process; 2) Actively engaging in key international multi-stakeholder processes that are pursuing MPAs and other zoning efforts; 3) Building constructive relationships among ocean industries and other ocean zoning stakeholders; 4) Creating practical experience by constructively engaging in ocean zoning developments in a specific regions.

Ontogenetic spatial distributions of red grouper (Epinephelus morio) and gag grouper (Mycteroperca microlepis) in the U.S. Gulf of Mexico

2017 ◽  
Vol 193 ◽  
pp. 129-142 ◽  
Author(s):  
Arnaud Grüss ◽  
James T. Thorson ◽  
Skyler R. Sagarese ◽  
Elizabeth A. Babcock ◽  
Mandy Karnauskas ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Spatial Distributions ◽  
Epinephelus Morio ◽  
Red Grouper ◽  
Gag Grouper ◽  
The U.S ◽  
Mycteroperca Microlepis
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