scholarly journals Baseline seabed habitat and biotope mapping for a proposed marine reserve

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1446 ◽  
Author(s):  
Sonny T.M. Lee ◽  
Michelle Kelly ◽  
Tim J. Langlois ◽  
Mark J. Costello

Seabed mapping can quantify the extent of benthic habitats that comprise marine ecosystems, and assess the impact of fisheries on an ecosystem. In this study, the distribution of seabed habitats in a proposed no-take Marine Reserve along the northeast coast of Great Barrier Island, New Zealand, was mapped using underwater video combined with bathymetry and substratum data. As a result of the boundary extending to the 12 nautical mile Territorial Limit, it would have been the largest coastal Marine Reserve in the country. Recreational and commercial fisheries occur in the region and would be expected to affect species’ abundance. The seabed of the study area and adjacent coastal waters has been trawled up to five times per year. Benthic communities were grouped by multivariate cluster analysis into four biotope classes; namely (1) shallow water macroalgaeEckloniasp. andUlvasp. on rocky substrata (Eck.Ulv); and deeper (2) diverse epifauna of sponges and bryozoans on rocky substrata (Por.Bry), (3) brittle starAmphiurasp. and sea anemoneEdwardsiasp. on muddy sand (Amph.Edw), and (4) hydroids on mud (Hyd). In biotopes Por.Bry, Amph.Edw and Hyd, there where boulders and rocks were present, and diverse sponge, bryozoan and coral communities. Fifty species were recorded in the deep water survey including significant numbers of the shallow-water hexactinellid glass spongesSymplectella rowiDendy, 1924 andRossella ijimaiDendy, 1924, the giant pipe demospongeIsodictya cavicornutaDendy, 1924, black corals, and locally endemic gorgonians. The habitats identified in the waters to the northeast of Great Barrier Island are likely to be representative of similar depth ranges in northeast New Zealand. This study provides a baseline of the benthic habitats so that should the area become a Marine Reserve, any habitat change might be related to protection from fishing activities and impacts, such as recovery of epifauna following cessation of trawling. The habitat map may also be used to stratify future sampling that would aim to collect and identify epifauna and infauna for identification, and thus better describe the biodiversity of the area.

2021 ◽  
Author(s):  
Campbell Murray

<p>With the possibility of deep-sea mining of marine mineral resources occurring in the near future, it is necessary to understand the potential impacts that mining may have on benthic communities. Previous simulated mining experiments have observed direct impacts of deep-sea mining (e.g., faunal mortality); however, indirect impacts of sedimentation were not understood. In New Zealand, there has been interest in mining the seabed of the Chatham Rise, but mining consents have been refused, partly due to the uncertainties of sedimentation impacts on benthic communities. A disturbance experiment conducted in 2019 on the Rise used a modified agricultural plough designed to create a sediment cloud that could result from mining. This disturbance was used to assess the resilience of benthic communities to sedimentation in a proposed future mining area. Macrofaunal and sediment samples were collected with a multicorer before, immediately after and one year after disturbance to assess the impact on the community and its ability to recover. Samplingevents took place in disturbed (physically run over by the plough and subjected to sedimentation) and undisturbed areas (subjected to sedimentation only) at each sampling period. Macrofaunal abundance significantly decreased in disturbed areas after disturbancebut not in undisturbed areas. However, community structure changed in both areas after disturbance; in disturbed areas this was mostly driven by changes in numerically dominant fauna, but in undisturbed areas by the more sensitive fauna which may provide an early warning sign for further changes under increased sedimentation. One year after disturbance, community structure had recovered in both areas. Abundance-based community structure correlated most strongly with C:N molar ratios in the sediment which increased after disturbance. Ecosystem function was measured by sediment community oxygen consumption (SCOC) which increased similarly in both disturbed and undisturbed areas after disturbance; SCOC may be a more sensitive measure than community structure in assessing sedimentation impacts. No correlations were found between SCOC and macrofaunal abundance, biomass, diversity or bacterial abundance. The results of this research are useful for managing the impacts of industries where sedimentation is an issue, such as for bottom trawl fisheries and deep-sea mining. The results highlight the importance of leaving unmined patches of seabed adjacent to or within mined areas, to aid the recovery of macrofaunal communities subjected to mining disturbance.</p>


Marine protected areas are currently being considered along the Oregon coast with the intention of rebuilding stocks. But stakeholders have questioned the effectiveness of reserves and little data exist with regard to marine reserves or the effects of fishing activities on benthic habitat along the Oregon coast. A unique opportunity exists to begin to collect such information because of <em>de facto </em>no-trawl reserves that exist along submerged coastal corridors where trans-oceanic communication cables have been laid across the seafloor. I intend to investigate a cluster of unburied cables, which extend off the Oregon coast just north of Bandon (summer, 2002). The corridor of reduced fishing impact, according to the trawl log book data, is approximately 2 miles wide and extends out from shore approximately 14 miles to about 70 fathoms. With the use of an ROV (remotely operated vehicle), commercial trawl data, and bathymetry data, I will be able to analyze the impact, if any, these <em>de facto </em>refuges have had on bottom-dwelling invertebrates and fish species of commercial importance. Specifically, I will analyze individual groundfish species associations with different substrate types and invertebrates within and outside of the cable corridor. This collaborative research will establish a credible baseline study on which to build further investigation regarding possible design of a successful marine reserve for groundfish and invertebrate species along the Oregon coast.


2021 ◽  
Author(s):  
◽  
Anjali Pande

<p>This study illustrates the importance of baseline surveys, why they are necessary and how best to conduct them. A proposed marine reserve site (the south coast of Wellington) was monitored for three years to establish a comprehensive baseline study. The results were used to recommend appropriate methodology for sampling in this area and also to establish which species are the best to use as indicator species to detect any possible change occurring in this area due to future reservation status. The 11 km stretch of coast surveyed, which included future reserve and control sites, was tested for heterogeneity, to prevent any future differences in sites being attributed to reservation status as opposed to natural variation. It was determined that an environmental gradient exists along the south coast, from east to west, most likely due to increasing wave exposure and increasingly strong tides and currents towards the west.  An established marine reserve (Kapiti Marine Reserve) was also monitored over the same period of time to establish what differences existed in size and abundance of key species between reserve and control sites. The data collected in this investigation were also compared to data collected immediately prior to reserve establishment to determine what changes had occurred over time. Results showed that sites inside the marine reserve supported a greater species abundance, and in some cases, larger size classes. There was some evidence for a general shift in the community structure particularly in algal plants. However, these results may have been confounded by the effect of one site that appeared to have a very high natural species diversity and abundance (even before reservation  status). It was concluded that the one-off survey conducted before establishment of this reserve was inadequate to use as a baseline against which to detect changes. No changes were found between the present study and the preliminary survey, although specific data analysis indicated a reserve effect. Continued sampling methodology for Kapiti Marine Reserve area was suggested. Raw data, on two key species (blue cod and rock lobster) from six marine reserves in New Zealand were investigated in an attempt to perform a statistical "meta-analysis" of the effects of marine reserves in New Zealand. A meta-analysis is different from a narrative review as it uses statistical methods to compare results across studies. This methodology has not been applied to studies of marine reserves before. The meta analysis conducted in the present investigation showed that generally marine reserves in New Zealand are having a positive effect, in terms of increasing size and abundance of individual species, as compared to control areas. There is some evidence for a latitudinal trend influencing the "effect size" (a statistical term indicating the magnitude of the treatment tested - in this case, reservation) of the reserves.</p>


2021 ◽  
Author(s):  
◽  
Anjali Pande

<p>This study illustrates the importance of baseline surveys, why they are necessary and how best to conduct them. A proposed marine reserve site (the south coast of Wellington) was monitored for three years to establish a comprehensive baseline study. The results were used to recommend appropriate methodology for sampling in this area and also to establish which species are the best to use as indicator species to detect any possible change occurring in this area due to future reservation status. The 11 km stretch of coast surveyed, which included future reserve and control sites, was tested for heterogeneity, to prevent any future differences in sites being attributed to reservation status as opposed to natural variation. It was determined that an environmental gradient exists along the south coast, from east to west, most likely due to increasing wave exposure and increasingly strong tides and currents towards the west.  An established marine reserve (Kapiti Marine Reserve) was also monitored over the same period of time to establish what differences existed in size and abundance of key species between reserve and control sites. The data collected in this investigation were also compared to data collected immediately prior to reserve establishment to determine what changes had occurred over time. Results showed that sites inside the marine reserve supported a greater species abundance, and in some cases, larger size classes. There was some evidence for a general shift in the community structure particularly in algal plants. However, these results may have been confounded by the effect of one site that appeared to have a very high natural species diversity and abundance (even before reservation  status). It was concluded that the one-off survey conducted before establishment of this reserve was inadequate to use as a baseline against which to detect changes. No changes were found between the present study and the preliminary survey, although specific data analysis indicated a reserve effect. Continued sampling methodology for Kapiti Marine Reserve area was suggested. Raw data, on two key species (blue cod and rock lobster) from six marine reserves in New Zealand were investigated in an attempt to perform a statistical "meta-analysis" of the effects of marine reserves in New Zealand. A meta-analysis is different from a narrative review as it uses statistical methods to compare results across studies. This methodology has not been applied to studies of marine reserves before. The meta analysis conducted in the present investigation showed that generally marine reserves in New Zealand are having a positive effect, in terms of increasing size and abundance of individual species, as compared to control areas. There is some evidence for a latitudinal trend influencing the "effect size" (a statistical term indicating the magnitude of the treatment tested - in this case, reservation) of the reserves.</p>


2021 ◽  
Author(s):  
Campbell Murray

<p>With the possibility of deep-sea mining of marine mineral resources occurring in the near future, it is necessary to understand the potential impacts that mining may have on benthic communities. Previous simulated mining experiments have observed direct impacts of deep-sea mining (e.g., faunal mortality); however, indirect impacts of sedimentation were not understood. In New Zealand, there has been interest in mining the seabed of the Chatham Rise, but mining consents have been refused, partly due to the uncertainties of sedimentation impacts on benthic communities. A disturbance experiment conducted in 2019 on the Rise used a modified agricultural plough designed to create a sediment cloud that could result from mining. This disturbance was used to assess the resilience of benthic communities to sedimentation in a proposed future mining area. Macrofaunal and sediment samples were collected with a multicorer before, immediately after and one year after disturbance to assess the impact on the community and its ability to recover. Samplingevents took place in disturbed (physically run over by the plough and subjected to sedimentation) and undisturbed areas (subjected to sedimentation only) at each sampling period. Macrofaunal abundance significantly decreased in disturbed areas after disturbancebut not in undisturbed areas. However, community structure changed in both areas after disturbance; in disturbed areas this was mostly driven by changes in numerically dominant fauna, but in undisturbed areas by the more sensitive fauna which may provide an early warning sign for further changes under increased sedimentation. One year after disturbance, community structure had recovered in both areas. Abundance-based community structure correlated most strongly with C:N molar ratios in the sediment which increased after disturbance. Ecosystem function was measured by sediment community oxygen consumption (SCOC) which increased similarly in both disturbed and undisturbed areas after disturbance; SCOC may be a more sensitive measure than community structure in assessing sedimentation impacts. No correlations were found between SCOC and macrofaunal abundance, biomass, diversity or bacterial abundance. The results of this research are useful for managing the impacts of industries where sedimentation is an issue, such as for bottom trawl fisheries and deep-sea mining. The results highlight the importance of leaving unmined patches of seabed adjacent to or within mined areas, to aid the recovery of macrofaunal communities subjected to mining disturbance.</p>


Author(s):  
Artem Lapenkov ◽  
Artem Lapenkov ◽  
Yury Zuyev ◽  
Yury Zuyev ◽  
Nadezhda Zuyeva ◽  
...  

Coastal zones have great diversity of resources. The shallow water zones contain the most of plant and benthic communities. A description of relief and type of ground is needed for the rigorous monitoring of biota and environmental condition of coastal zone. Generally, on the basis of these data the investigation methods of the coastal zone are selected. The shallows research strategy has been developed by us for northern part of the Lake Ladoga. If the coastal areas are characterized by great depth and flat topography, then sonar’s can be used to describe them and samples of ground can be taken by bottom grabs. In the Lake Ladoga these methods don’t operate correctly by reason of the compound bottom relief and the fact that a sizeable part of the bottom is occupied by hard ground. Therefore, our investigations base on the diving transect method of Golikov and Skarlato (1965). A diver moves along transects. He registers the depth, length to coastline, water temperature, relief and ground, edificators and records video. In the laboratory all these data are decoded and used for mapping of bays. Studies of plant communities have been performed and strategy for research of benthic communities in complex relief and hard ground conditions has been developed based on the descriptions of shallow waters. Description of the Malay Nikonovskia Bay bottom has given an opportunity to estimate changes in the bottom of the bay under the influence of the trout farm.


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