Cetacean occurrence and spatial distribution: Habitat modelling for offshore waters in the Portuguese EEZ (NE Atlantic)

Correia, Ana M.; Tepsich, Paola; Rosso, Massimiliano; Caldeira, Rui; Sousa-Pinto, Isabel

doi:10.1016/j.jmarsys.2014.10.016

Cited by 58 publications

(87 citation statements)

References 49 publications

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“…Sightings per unit of effort are commonly reported in the literature, including from platforms of opportunity (e.g. Arcangeli, Campana, Marini, & MacLeod, 2016;Correia et al, 2015), as the number of sightings per 100 km surveyed. Yet, this is more appropriate when obtaining data from ferries or cargo ships given that these platforms use established transect lines and do not change their course according to the animals' presence.…”

Section: Biological Factorsmentioning

confidence: 99%

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Analysis of occurrence patterns and biological factors of cetaceans based on long‐term and fine‐scale data from platforms of opportunity: Madeira Island as a case study

et al. 2018

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Management and conservation issues are addressed through the identification of areas of particular importance, which requires the acquisition of baseline information on species distribution and dynamics. These types of data are particularly difficult to obtain at high resolution for large marine vertebrates like cetaceans, given that dedicated surveys are complex and logistically expensive. This study uses daily presence–absence sighting data of cetaceans collected year‐round from whale‐watching boats to support the theory that fine‐scale data obtained from platforms of opportunity can provide valuable information on species occurrence and group dynamics. Data from 7,551 (daily) sightings comprising 22 species were collected from 3,527 surveyed days over 11 years (mean of 321 days per year, SD = 17) in the pelagic environment of Madeira Island. Cetaceans were observed on 92% of the surveyed days, and a mean of 15.4 (SD = 1.5), 8.2 (SD = 2.0) and 2.1 (SD = 1.2) species were recorded per year, month, and day, respectively. There were significant differences in the number of species per month (p < .001), with the highest diversity recorded in June. At least nine species, comprising 96% of all sightings, were found to use the Madeiran waters on a regular basis, such as the Atlantic spotted dolphin (Stenella frontalis), the short‐beaked common dolphin (Delphinus delphis), the bottlenose dolphin (Tursiops truncatus), and others featured in the Red List of the International Union for Conservation of Nature as Endangered, Vulnerable, and Data Deficient. In addition, 10 species were found to use the Madeiran waters for travelling, feeding, resting, socializing and calving, which suggests that the southern and southeastern waters of Madeira Island constitute an area of interest for cetaceans. This study characterizes the cetaceans’ community structure (occurrence, aggregation sizes, behaviours, proportion of calves, and inter‐specific relationships) of a poorly studied region, providing important information for managers. Finally, the advantages and limitations of using fine‐scale data from a type of platform of opportunity that is increasing along coastlines globally are discussed.

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Section: Biological Factorsmentioning

confidence: 99%

“…surveys with constant linear effort routes (e.g. Arcangeli, Marini, & Crosti, , ; Correia, Tepsich, Rosso, Caldeira, & Sousa‐Pinto, ), fishing vessels with non‐regular routes (e.g. Prieto, Tobeña, & Silva, ; Silva et al, ; Tobeña et al, ) and whale‐watching boats with targeted observational efforts (e.g.…”

Section: Introductionmentioning

confidence: 99%

Analysis of occurrence patterns and biological factors of cetaceans based on long‐term and fine‐scale data from platforms of opportunity: Madeira Island as a case study

et al. 2018

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“…Furthermore, the implementation of effective and long‐term monitoring plans is limited by the high costs of dedicated surveys at sea. Platforms of opportunity (e.g., whale watching vessels (Hauser et al , Koslovsky et al ), commercial ships, including cargo and passenger ships (Williams , Kiszka et al , Correia et al ), and oceanographic vessels (Friedlaender et al , Barlow and Forney )) represent a good and cost‐effective alternative, allowing for collection of data over extended periods, with sustainable expenses (Williams , Evans and Hammond ). One of the main requirements of an effective monitoring plan is its representativeness, its reproducibility, and repeatability over time, to allow direct comparison of data (Boitani and Fuller ).…”

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confidence: 99%

Fin whale seasonal trends in the Pelagos Sanctuary, Mediterranean Sea

Cominelli¹,

Moulins

Rosso

et al. 2015

Jour. Wild. Mgmt.

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Since 2009, a cetacean presence and distribution long-term monitoring study has been ongoing in the Pelagos Sanctuary, a pelagic marine protected area located in the northwestern Mediterranean Sea. One of the objectives of this study is to assess trends in cetacean presence and distribution to achieve good environmental status (GES) of pelagic marine waters. We assessed the density variability of the fin whale (Balaenoptera physalus) in the Pelagos Sanctuary. We used data collected during summer months (Jun-Sep) from 2009 to 2013, along 2 fixed transects crossing the Pelagos Sanctuary, using ferries as platforms of opportunity. We compared 2 un-corrected indexes: the linear encounter rate and density index, computed applying distance sampling methodology to select the most precise method. We also evaluated the effect of environmental covariates (e.g., platform height, Beaufort sea state, wind speed and direction, cloud cover and rain, longitude, latitude) on abundance and density estimation. Finally, we defined an unbiased index and used it to analyze the temporal and spatial variability of fin whale density in the Pelagos Sanctuary. Fin whale density along the 2 transects varied on a yearly basis, with a peak in 2012 and 2013. Variability also occurred on a monthly basis, with a peak during the first half of the season. A longitudinal and a depth gradient were also evident, confirming differences in species displacement in the area. These results are consistent with previous studies, and update current knowledge of species presence in the area. The protocol tested in this work can be easily applied to the other cetacean species inhabiting the Pelagos Sanctuary providing a novel and cost-effective method to assess long-term trends in cetacean distribution and detect incipient changes in species density. Ó

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“…Within the central and eastern groups of islands, fishing events that took place in the vicinity of seamounts were the most affected by dolphin interaction. Common dolphins are frequently sighted around seamounts in the Azores and possibly use these remote sites as feeding areas, taking advantage of the localized abundance of prey items [19, 40, 41]. …”

Section: Discussionmentioning

confidence: 99%

Predicting Interactions between Common Dolphins and the Pole-and-Line Tuna Fishery in the Azores

et al. 2016

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Common dolphins (Delphinus delphis) are responsible for the large majority of interactions with the pole-and-line tuna fishery in the Azores but the underlying drivers remain poorly understood. In this study we investigate the influence of various environmental and fisheries-related factors in promoting the interaction of common dolphins with this fishery and estimate the resultant catch losses. We analysed 15 years of fishery and cetacean interaction data (1998–2012) collected by observers placed aboard tuna fishing vessels. Dolphins interacted in less than 3% of the fishing events observed during the study period. The probability of dolphin interaction varied significantly between years with no evident trend over time. Generalized additive modeling results suggest that fishing duration, sea surface temperature and prey abundance in the region were the most important factors explaining common dolphin interaction. Dolphin interaction had no impact on the catches of albacore, skipjack and yellowfin tuna but resulted in significantly lower catches of bigeye tuna, with a predicted median annual loss of 13.5% in the number of fish captured. However, impact on bigeye catches varied considerably both by year and fishing area. Our work shows that rates of common dolphin interaction with the pole-and-line tuna fishery in the Azores are low and showed no signs of increase over the study period. Although overall economic impact was low, the interaction may lead to significant losses in some years. These findings emphasize the need for continued monitoring and for further research into the consequences and economic viability of potential mitigation measures.

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Cetacean occurrence and spatial distribution: Habitat modelling for offshore waters in the Portuguese EEZ (NE Atlantic)

Cited by 58 publications

References 49 publications

Analysis of occurrence patterns and biological factors of cetaceans based on long‐term and fine‐scale data from platforms of opportunity: Madeira Island as a case study

Analysis of occurrence patterns and biological factors of cetaceans based on long‐term and fine‐scale data from platforms of opportunity: Madeira Island as a case study

Fin whale seasonal trends in the Pelagos Sanctuary, Mediterranean Sea

Predicting Interactions between Common Dolphins and the Pole-and-Line Tuna Fishery in the Azores

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