Using Cost-Effective Surveys From Platforms of Opportunity to Assess Cetacean Occurrence Patterns for Marine Park Management in the Heart of the Coral Triangle

Sahri, Achmad; Mustika, Putu Liza Kusuma; Purwanto, Purwanto; Murk, Albertinka J.; Scheidat, Meike

doi:10.3389/fmars.2020.569936

Cited by 7 publications

(8 citation statements)

References 101 publications

(114 reference statements)

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“…The NOAA-SWFSC surveys covered the entire Guatemalan oceanic zone where those species are typically found, while this study sampled only about a third of the same zone; thus, reducing the probability of encountering pelagic species. Also, some species are gregarious by nature and might be more difficult to spot and identify (Sahri et al, 2020). The total number of small cetacean species identified in this study was smaller than that reported for the neighboring country of Mexico (15 species; Rosales-Nanduca et al, 2011), and other countries of the eastern tropical Pacific including Costa Rica (12 species; May-Collado et al, 2005) and Colombia (12 species; Palacios et al, 2012).…”

Section: Cetacean Biodiversity Abundance and Spatial Distributioncontrasting

confidence: 57%

Spatial Distribution and Abundance of Small Cetaceans in the Pacific Waters of Guatemala

et al. 2021

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The establishment of marine protected areas (MPAs) requires a thorough assessment of the abundance, distribution, and habitat preferences of a variety of marine species. Small cetacean spatial distribution and abundance were examined in the Pacific waters of Guatemala to provide this information. Boat surveys were conducted for 38 months between January 2008 and June 2012. A total of 64,678 cetaceans in 505 sightings from nine Delphinidae species were recorded. Three species, referred to as common species, accounted for 90% (n = 456) of all sightings. They included Tursiops truncatus (56%, n = 278), Stenella attenuata (29%, n = 143), and Stenella longirostris (7%, n = 35). Group size was significantly different among the common species (p < 0.001). S. longirostris had the largest group size (444 ± 75 dolphins), followed by S. attenuata (28 ± 5 dolphins), and T. truncatus (15 ± 2 dolphins). T. truncatus was the most common in the study area (0.02 ± 0.002 sightings/km of survey effort), and S. attenuata (0.37 ± 0.16 dolphins/km) and S. longirostris (1.62 ± 0.41 dolphins/km) were the most abundant in the neritic (≤200 m depth) and oceanic zones (≥200 m depth), respectively. The wide-ranging distribution of T. truncatus overlapped with the distribution of S. attenuata in the neritic zone and S. longirostris in the oceanic zone. Little overlap was observed in the distribution of S. attenuata and S. longirostris. Most hot spots (∼66%) were in the oceanic zone and no hot spots were near or in the MPAs. Hot spots were identified along the 200 m isobath, the Middle America trench, and the San José Canyon. These could be areas of high productivity where dolphins concentrate to feed. To the north of the San José Canyon, five species of small cetaceans were observed in a stretch of the neritic zone including three MPAs. No other section of this zone had such high diversity. Results need to be taken with caution given the small sample size. Our results suggest that the protection of small cetaceans needs to consider the creation of oceanic MPAs that should be integrated into the existing network.

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Section: Cetacean Biodiversity Abundance and Spatial Distributioncontrasting

confidence: 57%

Spatial Distribution and Abundance of Small Cetaceans in the Pacific Waters of Guatemala

et al. 2021

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“…Bryde's whales have also been observed west of Lovina in the Buleleng waters of north Bali (Mustika, personal observation, currently listed as the Buleleng IMMA), indicating that the island Province of Bali may play an important role in the conservation of this species. Bryde's whales have also been observed in the Wakatobi National Park (Sahri et al, 2020; the Wakatobi IMMA), Raja Ampat in West Papua (Ender et al, 2014; candidate IMMA) and Savu Sea and Surrounding Areas IMMA (Marine Mammal Protected Areas Task Force, 2021c). The confirmed sightings of Bryde's whales in this study, and the likelihood that eight out of 19 unidentified baleen whales (Table 1) were also Bryde's whales, add to the postulation that the study area is an important feeding habitat and a possible breeding or nursing ground for this species.…”

Section: Lessons Learned From the Training (Objective 4) And Future Research And Actionsmentioning

confidence: 99%

A Rapid Assessment of the Marine Megafauna Biodiversity Around South Bali, Indonesia

Mustika

Williams²,

Kadarisman

et al. 2021

Front. Mar. Sci.

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A low-cost, small-boat, rapid assessment survey was conducted on the waters off the southern Peninsula of Bali. The objectives were: (1) to conduct an inventory of cetacean species in the study area; (2) to map cetacean distribution to inform the design of the Badung MPA; (3) to estimate relative abundance of cetaceans and record information on presence and distribution of other marine megafauna; and (4) to train observers in the use of distance sampling methods. The survey adopted a “training while doing” approach to build local capacity for marine biodiversity monitoring, while collecting a snapshot of data to assess species richness and distribution. The survey accomplished its first two objectives, but due to violation of underlying assumptions, had mixed success with the third objective. Our survey revealed that the waters off the southern Peninsula of Bali support a rich cetacean fauna, with at least seven cetacean species, other marine megafauna, and avian species. Seven cetacean species found on our survey include: spinner dolphin (Stenella longirostris), pantropical spotted dolphin (Stenella attenuata), Fraser’s dolphin (Lagenodephis hosei), Risso’s dolphin (Grampus griseus), bottlenose dolphin (Tursiops sp.), Bryde’s whale (Balaenoptera edeni), and sperm whale (Physeter macrocephalus). Density estimates were low for all whales combined, but seem implausibly high for dolphins; likely due to violation of assumptions of distance sampling methods. Future surveys should include sufficient time for training to generate reliable abundance estimates. A dedicated bycatch study is needed to understand sustainability of bycatch mortality relative to reliable abundance estimates.

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“…Visual line‐transect surveys employed to observe cetaceans in the ocean are mainly conducted using ships and aircraft (Hammond et al, 2021). Buckland et al (2001) described line‐transect sampling method in detail; in brief, transect lines are placed randomly using a design in which each part of the study area has an equal probability of being surveyed (Sahri et al, 2020; Thomas et al, 2007). However, using ship and aerial surveys over relatively large areas can be prohibitively expensive (Sahri et al, 2020; Thomas et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Buckland et al (2001) described line‐transect sampling method in detail; in brief, transect lines are placed randomly using a design in which each part of the study area has an equal probability of being surveyed (Sahri et al, 2020; Thomas et al, 2007). However, using ship and aerial surveys over relatively large areas can be prohibitively expensive (Sahri et al, 2020; Thomas et al, 2007). Furthermore, without the use of dedicated sighting survey vessels, it is difficult to cover large areas and increase the frequency of surveys using the transect sampling methods described by Buckland et al (2001).…”

Section: Introductionmentioning

confidence: 99%

Can the annual bycatch per unit effort of common dolphins (Delphinus delphis) be used to index the species' relative abundance in the East Sea of Korea?

Yoo,

Park

2023

Marine Mammal Science

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Visual line‐transect surveys are widely used to estimate the abundance of cetacean populations; however, this method can be prohibitively expensive. Thus, a less expensive alternative method was investigated in the present study, i.e., whether temporal changes in the bycatch per unit effort (BPUE) of cetaceans could be used to index the changes in their abundance. Specifically, the relationship between the annual BPUE of two main bycatch fisheries and the relative abundance of common dolphins (Delphinus delphis) was examined in 2012, 2013, 2015, and 2017 when vessel‐based line‐transect surveys were conducted in the coastal region of the East Sea of Korea. The encounter rate (individuals/km) by study year was significantly correlated with the annual BPUE of set nets. An increase in the density (individuals/km2) of common dolphins, estimated according to a hazard‐rate key function by study year, was associated with an increase in the BPUE of set nets. These results suggest that the annual BPUE of common dolphins could be used to index the species' relative abundance. The BPUE of set nets, which are fixed in coastal regions, reflect the densities of common dolphins in the coastal regions better than that of gill nets used in coastal and offshore regions.

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Using Cost-Effective Surveys From Platforms of Opportunity to Assess Cetacean Occurrence Patterns for Marine Park Management in the Heart of the Coral Triangle

Cited by 7 publications

References 101 publications

Spatial Distribution and Abundance of Small Cetaceans in the Pacific Waters of Guatemala

Spatial Distribution and Abundance of Small Cetaceans in the Pacific Waters of Guatemala

A Rapid Assessment of the Marine Megafauna Biodiversity Around South Bali, Indonesia

Can the annual bycatch per unit effort of common dolphins (Delphinus delphis) be used to index the species' relative abundance in the East Sea of Korea?

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