migration

Importance of Yarari Sanctuary for Minke Whale

A new collaborative study provides new insight into how two species of minke whales utilize the Caribbean and neighboring Atlantic waters throughout their life cycle. The findings add further conservation value and significance to the relatively new Yarari marine sanctuary of the Netherlands. By combining scientific, citizen science and public information, this study provides key information which will help guide conservation efforts moving forward.

Minke whales are the smallest of the “great whales” and can be found in waters world-wide. There are actually two different species of Minke whale, the common minke whale, or northern minke whale (Balaenoptera acutorostrata) and the Antarctic minke whale, or southern minke whale (Balaenoptera bonaerensis).

Yarari Sanctuary

Minke whales are known to migrate over long distances, with both species using the warm waters of the Caribbean to breed and calf during the winter months. Within the Caribbean, there are a number of marine protected areas, such as the Yarari Marine Mammal and Shark Sanctuary, which includes the territorial waters around Bonaire, Saba, and St. Eustatius. In addition to providing vital protection of the marine ecosystem, the Yarari Sanctuary is used to help focus research for greater insight into the life cycles and migration patterns of both resident and migratory species. Understanding how these species travel during the year and use Caribbean waters is critical in designing effective conservation plans in the future.

New Study

A recent study brought together a wide array of researchers and conservation groups including the Institute of Environmental Sciences from Leiden University and the Aruba Marine Mammal Foundation. This study reviewed literature, citizen science and scientific records to compile spatial and temporal data for both species of minke whales. The goal of the study was to learn more about how these species use the Wider Caribbean Area throughout their life cycles.

In total, 130 records were collected, most of which were from scientific studies (100) and the rest from citizen science (30). Minke whales are notoriously inquisitive, frequently approaching boats, which makes them the perfect species to be spotted by citizen scientists. Improvements in civilian camera equipment, and increased initiatives to record and share biodiversity observations on social networks and public databases have led to a recent surge in citizen science reports for all species.

Findings

Photo credit: Hans Verdaat

This study was able to integrate scattered species records to provide new insights that point to the importance of the Yarari Sanctuary which lies in the center of an Eastern Caribbean wintering area for the common minke whale and thus add conservation value and significance to this relatively new marine sanctuary of the Netherlands. These new insights are in large part thanks to two previous studies conducted by Wageningen University & Research together with the Saba Bank Managing Unit and were generously funded by the Ministry of Agriculture, Nature and Food Quality (LNV). These latter results were aligned with similar studies and were found to be consistent with large-scale seasonal migration routes of the Minke whales.

Interestingly, this study highlighted that although it was previously believed that only the northern minke whale used the Gulf of Mexico, there were confirmed stranding incidents involving both species. Furthermore, the fact that there were strandings of minke whales throughout the year suggested that some whales stay year-round within the Gulf.

Report your Sightings

Every sighting can provide useful data that can contribute to the understanding needed to protect these species. Help further conservation efforts by reporting your (minke) whale (or other species) sightings and photos on the website Observation.org or download the free app (iPhone (iObs) & Android (ObsMapp)). These tools are available in over 40 languages and can be used by biologists, citizens and tourists alike.

For more information you can find the full report on the Dutch Caribbean Biodiversity Database by clicking the button below.

https://www.dcbd.nl/document/spatial-temporal-distribution-minke-whales-...

 

Article published in BioNews 46

 

Date
2021
Data type
Media
Theme
Education and outreach
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
Saba
Saba bank
St. Eustatius
St. Maarten
Author

Habitat utilization and migration in juvenile sea turtles.

Sea turtles are basically creatures that spend their entire lives in marine or estuarine habitats.Their only remaining reptilian ties to terrestrial habitats are for nesting and restricted cases of basking. Consequently.physiological. anatomical. and behavioral adaptations have evolved largely in response to selection in the aquatic environment and sea turtles share many common elements with liirger tislics and cetaceans in their habitat utilization and migrations. A generalized habitat model may he con- structed for sea turtles based on ontogenetic stages (Figure 6.1):

I. Early juvenile nursery habitat (usually pelagic and oceanic).
2. Later juvenile developmental habitat (usually demersal and neritic).

3. Adult foraging habitat.
4. Adult inter-nesting andfor breeding habitat. 

All sea turtles move immediately to the sea after hatching, usually after dark, and swim actively offshore. Most then undertake a mostly passive, denatant {sensu Jones)' migration drifting pelagically in oceanic gyre systems. Subsequently, after a period of years, these now larger and older juveniles actively recruit to demersal neritic dcvelopmentai habitats in the tropical and temperate zones. Demersal juve- niles in some temperate zone populations make seasonal migrations to foraging areas at higher latitudes in summer and lower latitudes in winter (see below) while those in tropical areas are more localized in their movements, When approaching maturity, pubescent turtles move into adult foraging habitats. In some populations adult habitats are geographically distinct from juvenile developmental habitats;24in others they may overlap or coin~ide.U~p.~on maturity as the nesting season approaches adults make a contranatant migration toward the nesting beaches. Most mating occurs t poorly defined courtship areas that are clone KÃthe nesting beaches relitlive lo the distant foraging areas. Afler mating the females move to their respcclivc nesting beaches.'-* Courtship areas may be directly HITthe nesting beaches,*or remote from the beaches,'" depending on the population. During the nesting season, females usually become resident in the internesting habitat in the vicinity of the nesting beach." The focus of the present paper is habitat utilization and migration of juvenile sea turtles and nursery and developmental habitats. 

 

Date
1997
Data type
Book
Theme
Research and monitoring

This Little Island is a Haven for Migratory Shorebirds

Fernando and I are at our one of our “high density” points (counting stations) on the Cargill Salt Production Facility in southern Bonaire. We are driving the dike roads stopping every 400m to carry out a 6-minute count, recording all the birds in a 200m radius around our point. A second team, Jeff Gerbracht (Cornell Lab of Ornithology) and Binkie van Es (St. Maarten Nature Foundation) are covering another part of the facility. The conditions can only be described as harsh—non-stop winds of 25-30 knots, blazing sun and salt foam blowing at us constantly. But the shorebirds love it, and so do we—there are not very many places where you can see such large concentrations and diversity of shorebirds so close.

We have so far encountered over 20 species of shorebirds and waterbirds using the Cargill ponds, including American Flamingo, Great Blue Heron, Tricolored Heron, Reddish Egret, Black-bellied Plover, Snowy Plover, Greater yellowlegs, Lesser Yellowlegs, Ruddy Turnstone, Stilt Sandpiper, Least Sandpiper, Semipalmated Sandpiper, Western Sandpiper, Short-billed Dowitcher, Red Knot and more. Depending on where the point is in the Cargill Facility, we might encounter zero birds in areas of deeper water, or mixed flocks numbering in the hundreds or even thousands in areas with shallow water or exposed flats.

How and why did these surveys get started? Two years ago, I had the chance to visit and tour the Cargill Salt Production Facility for the first time, thanks to Daniel Deanda (Production Manager), who attended our Wetlands Education Training Workshop in May 2014, hosted by STINAPA Bonaire. I was amazed at the number of migratory shorebirds and waterbirds on the property, including the stunningly beautiful American Flamingos which dot the stark landscape like pink flowers. I recognized that this small island and even smaller site was probably hugely important to migrant and wintering shorebirds, perhaps even qualifying as a Western Hemisphere Shorebird Reserve Network (WHSRN) site, a program set up by Manomet 30 years ago to protect the most important breeding, stopover, and wintering habitats for shorebirds throughout the Americas.

Date
2016
Data type
Media
Theme
Education and outreach
Research and monitoring
Geographic location
Bonaire
Author

Bird Communities of Contrasting Secondary Habitats of Bonaire, in the Arid South-Eastern Caribbean

We studied the bird communities of five contrasting semi-natural habitats of Lac Bay, Bonaire, South- eastern Caribbean, during the fall of 2011. A total of 420 point counts were conducted in five different habitats and 63 species were detected. Of these, 31 (49%) were migrants, 24 (38%) were residents, 6 (10%) occurred both as residents and migrants and 2 (3%) were migrants that possibly or irregularly breed. Most migratory species were shorebirds and waders (76%). The bird communities of the ve habitats studied showed signi cant differences in species composition and associated community parameters. Mangrove thicket and salt at habitats had roughly a two-fold higher total species richness and a four-fold higher migratory species richness compared to woodland habitats. In woodland habitats, breeding residents dominated, whereas migratory shore and waterbirds dominated in salt at habitat. The Northern Waterthrush, Parkesia noveboracensis, and Barn Swallow, Hirundo rustica, were the numerically most important migratory passerines. The Reddish Egret, Egretta rufescens, a globally Near-Threatened species, ranked among the top 10 most abundant species of the Lac Bay salt at habitat. Our results suggest that the relatively expansive hypersaline wetlands of Bonaire (of which Lac is only a small part) may be of special signi cance to migratory shore and waterbirds. In contrast to other areas of the Caribbean, invasive exotic birds so far play a minor role in the communities studied. 

Date
2014
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao

The effects of the lunar cycle on plankton density, diversity, and diel migration in the coastal waters of Bonaire, N.A.

The lunar cycle is a key environmental factor influencing the feeding, reproduction, and migration of many marine organisms, including fish, invertebrates, and zooplankton. To investigate the influence of lunar stage on zooplankton density and diversity in Bonaire, Netherlands Antilles, samples of zooplankton were collected from surface waters at midday and at night at each stage of a complete lunar cycle. The purpose of this research was to determine 1) whether zooplankton in surface waters are more abundant during the night or day, 2) during which stage in the lunar cycle zooplankton densities are the highest, 3) whether diel period has an effect on the biodiversity of plankton, and 4) whether lunar stage has a effect on biodiversity of zooplankton. It was found that microzooplankton and macrozooplankton occurred in higher densities at night. The highest microzooplankton density occurred during the waning gibbous phase and the highest macrozooplankton density occurred during the first quarter (289.7 individuals m-3, 28.4 individuals m-3, respectively). Organisms from the classes maxillopoda, malacostraca, and chaetognatha were most prevalent in all samples. The full moon showed both the greatest and least taxonomic diversity among samples with 19 different classes (avg. 13.4) found during the nighttime sample and 7 appearing during the midday sample. Due to an abundance of eggs during the waning gibbous lunar stage it is suggested that lunar spawning has an impact on plankton density and composition.

This student research was retrieved from Physis: Journal of Marine Science VI (Fall 2009)19: 27-34 from CIEE Bonaire.

Date
2009
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Author

Diel vertical migration and luminescent activity of bioluminescent dinoflagellates in Bonaire, Dutch Caribbean

Bioluminescence is a cold-light produced by chemical reactions and has been observed in over 90% of marine organisms. The largely speculated adaptive significance behind bioluminescent activity includes defense against predators, prey distraction, and communication. Bioluminescent photosynthetic dinoflagellates play a major role in the ocean’s primary production. Daily vertical migrations (DVMs) through the water column are phototactic movements, where photosynthetic dinoflagellates return to the surface during daylight to photosynthesize. It was hypothesized that dinoflagellates migrate to the surface in daylight and to depth (4 m) in darkness. It was also hypothesized that chemically provoked luminescent activity would be greater after prolonged exposure to daylight rather than darkness. Samples were collected at am and pm intervals using a 30 cm diameter plankton tow with 20 µm netting. Density of dinoflagellates were estimated under a compound microscope using a Neubauer-improved haemocytometer. Luminescent assays were performed by adding 5% acetic acid to the samples and timing the duration of luminescence in s. A two-way ANOVA with depth and time as factors revealed a significant interaction: at night 4 m density was significantly higher than 0 m density, and in the morning 0 m density was significantly higher than 4 m density. Luminescent activity in the morning was significantly higher than in the evening. A DVM of bioluminescent dinoflagellates was exhibited as a result of a phototactic movement. This study aimed to understand the relatively unknown bioluminescent dinoflagellate activity of one shallow coastal area in Bonaire, Dutch Caribbean.

This student research was retrieved from Physis: Journal of Marine Science XI (Fall 2012)19: 70-74 from CIEE Bonaire.

Date
2012
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Author

First visual record of a living basking shark Cetorhinus maximus in the Caribbean Sea

The occurrence of basking sharks in the Caribbean Sea is only recently documented by satellite tagging studies, which show that some individuals migrate through the region en route from waters off the east coast of the USA to waters off northeastern South-America. The observation of a basking shark on 7 November 2013 ca. 130 km north-northeast of Aruba during an aerial survey of marine mammals in the waters around the Dutch Leeward Islands is reported. This observation constitutes the rst visual record of a living basking shark in the Caribbean. 

Date
2016
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Aruba

Island–island and island–mainland movements of the Curaçaoan long-nosed bat, Leptonycteris curasoae

Of the 3 species comprising the genus Leptonycteris Miller, L. curasoae has been the least studied with respect to its long-distance flights and potential for seasonal migrations. We studied long-distance movements between islands and between islands and the mainland in the Curaçaoan long-nosed bat. We used mark–recapture with periodic sampling and marking of bats in Aruba, Curaçao, Bonaire, and 1 location (Butare) in Falcón State, on the Venezuelan coastline. Between October 2008 and April 2014, we captured a total of 7,518 individuals at 11 sites (Aruba: n = 1,827, Curaçao: 778, Bonaire: 4,128, and Butare: 785). Between 78.3% and 98.0% of the bats captured at each island and mainland were marked, and the overall percentage of recaptured animals across all sampling sites was 8.31% (n = 529). L. curasoae inhabits the 3 islands year-round. On each island, it roosts in several caves, which can be used alternatively by the same individuals. Despite being a resident species, L. curasoae can perform long-distance oversea flights between islands and between islands and the South American mainland. A total of 11 long-distance flights were recorded (2 Bonaire–Aruba, 4 Bonaire–Curaçao, 1 Curaçao–Bonaire, 1 Bonaire– Venezuela, and 3 Aruba–Venezuela). We propose that populations of this species in Aruba, Curaçao, Bonaire, and Falcón State, Venezuela, exchange individuals, and part of the insular populations migrate seasonally southward as a response to cyclical changes in local resource availability and the yearly reproductive regime. 

Date
2015
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao