Humpback and minke whale acoustic presence with reference to fish sounds and ambient noise levels at Saba Bank, Caribbean Windward Dutch Islands
Risch, D. ; Haan, D. de - \ 2016
IMARES (Report / IMARES C067/16) - 22
megaptera novaeangliae - whales - acoustics - sounds - netherlands antilles - monitoring - saba - megaptera novaeangliae - walvissen - geluidsleer - geluiden - nederlandse antillen - monitoring - saba
The Antillean Island chain is a known breeding and calving ground for North Atlantic humpback whales (Megaptera novaeangliae). However, while most research efforts for this species have focused on the largest aggregation of whales, located on Silver Bank, off the northern coast of the Dominican Republic, there are still significant knowledge gaps with respect to humpback whale movements along the Antillean Island chain. Even less is known about the spatio-temporal distribution of other marine mammal and fish species in the region. This report summarizes analysis results of acoustic data (10-8000 Hz effective analysis bandwidth recorded at a 25% duty cycle), recorded on the north east of Saba Bank from October 2011 to April 2012. The results show the consistent presence of humpback whales in the vicinity of Saba Bank during their winter breeding season, occasional presence of minke whales and the presence of sound producing fish assemblages. Humpback whale song occurred from the end of December to the end of the recording period in April. From February to April humpback whale song was recorded on more than 89 % of all recording days, though it occurred most frequently in March. All recording days in March showed song presence, with an average of 8.5 ± 2.8 (mean ± SE) hours of recorded song per day. In contrast, for minke whale (Balaenoptera acutorostrata) 48 pulse trains (n = 32) were detected less frequently between February to April 2012. A variety of unidentified fish sounds were present throughout the recordings. Although the occurrence of these sounds was not quantified, notable fish choruses (e.g. grouper spp. Epinephelinae) consisting of one to two distinct pulsed calls in the frequency range of 100 - 600 Hz were documented from October to December 2011 in particular. The results of this pilot project highlight the feasibility of using passive acoustic monitoring (PAM) to explore year-round marine mammal and fish presence and distribution in otherwise understudied and remote field sites.
Marine assessment guideline for BOPEC and Nustar operations
Slijkerman, D.M.E. ; Meesters, H.W.G. ; Becking, L.E. - \ 2016
IMARES (Report / IMARES C056/16) - 26
environmental monitoring - bonaire - sint eustatius - oil spills - bleaching - saba - milieumonitoring - bonaire - sint eustatius - olieverontreinigingen - bleking - saba
As part of the permit, Rijkswaterstaat requested an ecological monitoring and evaluation framework guideline to accompany the permit-application for the activities of BOPEC (Bonaire) and Nustar (St. Eustatius), related to the activities of the loading and unloading of oil and oil-related-products. IMARES has been asked to develop a tailored guideline to assist in the design of a monitoring plan by BOPEC and Nustar. The current document is the requested guideline. A complete monitoring proposal by the license holder must subsequently be developed on the basis of this guideline. The generic framework developed by Becking and Slijkerman (2012) was applied and made more specific for this guideline. The basic steps undertaken were: 1. Establishing the context in which the project will take place. 2. Scoping of the project activities, their pressures and the environmental descriptors relevant to the potential impact area. 3. Assessment and evaluation of the anticipated pressures on the selected biological and environmental descriptors. The guidance thus contains an overview of relevant activities and their pressures. In addition, biological descriptors were selected based on the most important relationships to the planned activities and anticipated pressures. The scope of monitoring is based on the major linkages between activities, -pressures and -ecosystem descriptors. A distinction is made between baseline and accident monitoring. Baseline monitoring is necessary to guarantee that background levels and patterns of change over time are known. This should be done also at control sites to make sure that a natural pattern (e.g. bleaching) is not confused as an effect of pollution on the impact sites. Both control sites and impact sites to perform baseline monitoring are recommended in this report. Accident monitoring is the assessment of the environmental status following accidents. Polluted sites should be identified and monitored. In parallel, all baseline monitoring should be continued. Due to wind and currents, there is a high likelihood that oil spilled at Nustar will float to the coast of Saba. Therefor it is necessary to check the coast of Saba as well after an oil spill. The baseline monitoring should be a continuous process with and regular effort, while accident related monitoring is incidental, only but directly after a spill or accident. Each type of monitoring requires different frequencies (Chapter 6).
A landscape ecological vegetation map of Saba (Lesser Antilles)
Freitas, J. de; Rojer, A.C. ; Nijhof, B.S.J. ; Debrot, A.O. - \ 2016
Den Helder : IMARES (Report / IMARES C195/15) - 48
vegetation mapping - vegetation - flora - islands - saba - vegetatiekartering - vegetatie - flora - eilanden - saba
A semi-detailed landscape-based vegetation map (scale: 1: 37,500) is presented for the 13 km2 Lesser Antillean steep volcanic island of Saba, Netherlands Caribbean. The map is based on a total of 49 vegetation plots that were sampled in 1999 using a stratified random sampling design and analysed using TWINSPAN cluster analysis. Three hundred and fourteen (314) plant species, representing 56% of the total known flora (565 species), were recorded in the sample plots. The principal lower sections of the island possess a tropical savannah climate whereas the upper slopes reaching a maximum altitude of 870 m can best be characterized as a tropical rainforest climate.
Monitoring the effect of cat removal on reproductive success in Red-billed Tropicbird colonies on Saba, 2013 - 2014: first season of results
Terpstra, M. ; Woude, E. van der; Wulf, K. ; Rijn, J. van; Debrot, A.O. - \ 2015
Den Helder : IMARES (Report / IMARES C103/15) - 32
animal welfare - wild animals - birds - cats - animal health - saba - feral cats - dierenwelzijn - wilde dieren - vogels - katten - diergezondheid - saba - verwilderde katten
One of the most deleterious invasive introduced predators worldwide is the domestic cat which has been found responsible for many island extinctions worldwide. Cats can live off both natural prey and garbage and can be a particularly serious threat to ground-nesting bird populations. Saba is an important location for the Red-billed Tropicbird, Phaethon aethereus and feral cats are thought to be the main reason for the low breeding success in the southern coastal colonies of this bird. To make proper decisions in invasive predator management, information is needed on the effects of cat removal on the tropicbird breeding success and the possible resulting increase in egg predation by rats in the case of any “mesopredator release effects”. In this study researchers collected the first season of data needed to assess the effect of cat removal on the breeding success of the tropicbird on Saba.
Pilot study on behaviour of sharks around Saba using acoustic telemetry - Progress report 2014
Winter, H.V. ; Vink, D. ; Beek, I.J.M. van - \ 2015
IJmuiden : IMARES (Report / IMARES Wageningen UR C026/15) - 21
haaien - saba - zeereservaten - telemetrie - migratie - verspreiding - universitair onderzoek - sharks - saba - marine protected areas - telemetry - migration - dispersal - university research
Worldwide many shark populations are in strong decline mainly due to fisheries. Population status of sharks in the Caribbean is still poorly known. In order to be able to take effective measures to protect sharks, insight in their spatial behaviour during different life stages is required. Do marine parks enhance shark populations and if so at what scale? This pilot study mainly aims at determining the feasibility of using telemetry around Saba and at a later stage at the Saba Bank and surrounding islands, e.g. what logistics and which co-operation, catching and deployment methods are required to set-up telemetric experiments for target shark species, and to get a first insight of the scale of movement patterns of the target shark species.
Lobster trap detection at the Saba Bank
Beek, I.J.M. van - \ 2012
Den Helder : IMARES (Report / IMARES Wageningen UR C091/12) - 35
zeekreeften - vallen - detectie - visserijbeheer - saba - lobsters - traps - detection - fishery management - saba
According to previous studies and anecdotal evidence there are a lot of lost lobster traps at the Saba Bank. One study estimated the loss to be between 210 and 795 lobster traps per year. The Saba Bank is an approximately 2,200 km2 submerged area and spiny lobster (Panulirus argus) is one of the main fisheries with an annual economic value over USD 1 million. The traps get lost due to a combination of bad weather moving or damaging traps and marker buoy lines, ship traffic running into and cutting marker buoy lines and removal of marker buoy or theft of traps by vandals. Lost traps are a concern for the Saba Bank fisheries management, because of the potential impact of ghost fishing by lost traps and the damage to the benthic environment. IMARES was commissioned by the Ministry of Economic Affairs, Agriculture and Innovation to advise on a method to detect lost lobster traps. The objective of this desk study was to provide information for the sustainable management of the lobster fisheries and the conservation of the Saba Bank. In this report we investigate the most efficient method for the detection of lost lobster traps from a small vessel in water between 15 and 50 meter depth. We not only address methods for the location of traps, but also recommend methods for the retrieval of traps and measurement of ghost fishing. Side scan sonar in combination with a magnetometer is recommended as the best, most efficient method to locate lost lobster traps in order to retrieve them. This is not necessarily the most cost-efficient method to respond to the problem of future traps loss, as preventive measures tend to be more effective and less costly than curative measures. However, a detection survey can be used to better estimate the magnitude of the problem of already lost traps. It is not realistic that a detection survey can locate all lost traps that are present on the Saba Bank.
Cruise report seabird and cetacean survey Saba bank expedition October 2011
Geelhoed, S.C.V. ; Verdaat, J.P. - \ 2012
Den Burg : IMARES (Report / IMARES Wageningen UR C062/12) - 13
zeezoogdieren - zeevogels - mariene ecologie - saba - sint-maarten (eiland) - sint eustatius - marine mammals - sea birds - marine ecology - saba - saint martin (island) - sint eustatius
In October 2011 an expedition took place to the Saba Bank, on board of the ship the Caribbean Explorer II. Main aim of the expedition was collecting data on underwater fauna and coral reefs. Apart from that data were collected on nutrients, water flow, sponges and seabirds and marine mammals. Data on the last group were collected by deploying acoustic data loggers, and by means of visual surveys. These visual surveys were conducted whenever the other activities permitted it. This cruise report presents an brief overview of the results obtained during the October 2011 survey. It contains a short day to day report, a full list of all birds, mammals and particular pieces of floating matter seen, and a brief presentation of the results. Furthermore the report contains a brief account of observed birds on Sint Maarten, since published accounts on the birdlife of the island are scarce.
A status report of nature policy development and implementation in the Dutch Caribbean over the last 10 years and recommendations towards the Nature Policy Plan 2012 - 2017
Debrot, A.O. ; Graaf, M. de; Henkens, R. ; Meesters, H.W.G. ; Slijkerman, D.M.E. - \ 2011
Den Burg : IMARES (Report / IMARES Wageningen UR C064/11) - 41
natuurbeleid - natuurbeheer - caribische eilanden - bonaire - saba - sint eustatius - nature conservation policy - nature management - caribbean islands - bonaire - saba - sint eustatius
Biodiversiteit voor de BES-eilanden: Bonaire, St. Eustatius en Saba : onderzoeksvragen en verplichtingen
Jongman, R.H.G. ; Meesters, H.W.G. ; Debrot, A.O. - \ 2010
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2080) - 65
biodiversiteit - mariene gebieden - natuurbescherming - bonaire - sint eustatius - saba - terrestrische ecosystemen - biodiversity - marine areas - nature conservation - bonaire - sint eustatius - saba - terrestrial ecosystems
Dit rapport geeft een overzicht van de biodiversiteit op en rond de eilanden Bonaire, St. Eustatius en Saba (BES) en de verplichtingen die voortkomen uit verdragen waar op dit moment de Nederlandse Antillen aan gebonden is. Het rapport geeft verder de belangrijkste onderzoeksprioriteiten, gerelateerd aan deze internationale verplichtingen voor zowel de mariene als de terrestrische biodiversiteit.
Biodiversity of the Saba Bank supports status of Particularly Sensitive Sea Area (PSSA)
Meesters, H.W.G. - \ 2010
IJmuiden : IMARES (Report / IMARES Wageningen UR no. C014/10) - 17
natuurbescherming - saba - biodiversiteit - atollen - larven - zeereservaten - nature conservation - saba - biodiversity - atolls - larvae - marine protected areas
This report contains a study regarding the biodiversity of the Saba Bank, one of the three largest atolls in the world. All scientific and anecdotic evidence suggests that the area is a hot spot of biodiversity and one of the few areas in the Caribbean that is still in a relatively pristine condition. The atoll is likely also important as a source of larvae for other areas in the region because of its enormous dimensions and diverse habitats. Major damage however may already be inflicted by the anchoring of large oil tankers. More scientific research is necessary with regards to the damage inflicted by anchoring and to the sustainability of current fishing practices, but to date there is already sufficient data to call for strong protection of the Saba Bank as soon as possible. Therefore, an application to the International Maritime Organization (IMO) to designate the Saba Bank as a Particularly Sensitive Sea Area (PSSA) in order to prevent possibly irreversible damage to the ecosystem and to enable sustainable protection of it’s vulnerable resources seems crucial and urgent.