Alexander Tewfik

Coral reefs are facing a constant barrage of human impacts, including eutrophication, overharvesting and climate change. While the local effects of overharvesting have been well-studied, regional nutrient loading from anthropogenic activities on land and global climate change-induced disturbances are increasing in magnitude and necessitating cross-...

Blood samples were obtained from the dorsal cervical sinus of free-ranging hawksbill sea turtles (Eretmochelys imbricata) collected at Glover's Reef Marine Reserve, 42 km east of the coast of Belize, for hematology and plasma biochemistry analysis. Unknown sex, subadult turtles (N = 32) were sampled in 2013 (n = 22) and 2017 (n = 10). To provide a...

Many species targeted by multi‐gear small‐scale fisheries in developing countries are poorly studied in terms of fisheries sustainability even as their contributions to biodiversity, livelihoods, export earnings and food security are well documented. This study presents new information on more than 150 fish species that constitute the bulk of small...

Coral reefs are facing a constant barrage of human impacts, including eutrophication, overharvesting and climate change. While the local effects of overharvesting have been well-studied, regional nutrient loading from anthropogenic activities on land and global climate change-induced disturbances are increasing in magnitude and necessitating cross-...

Macroalgal blooms are increasing on the Belize Barrier Reef (BBR) as scleractinian coral cover declines. Although some have attributed this to reduced grazing, the role of land-based nutrient pollution has not been assessed. Nutrient enrichment was quantified through macroalgal tissue analysis from Belize City to the offshore fore reef and at sever...

In Belize, the commercial harvest of spiny lobsters has occurred for approximately 100 years, provides critical livelihoods, and is the primary seafood export. We determined the first empirical estimate of size at maturity in Belize as well as eight fishery status indicators on several fishing grounds. The carapace lengths (CLs) at 50% maturity var...

In the face of climate change, warming oceans, and repeated mass coral bleaching, coral reef conservation is at a timely crossroads. There is a new urgency to support and strengthen a rich history of conservation partnerships and actions, while also building toward new actions to meet unparalleled global threats. The goal of this white paper is to...

Queen conch ( Lobatus gigas ) is a large herbivorous gastropod, found across the Caribbean, which forms the basis of important dive fisheries. Conch have a two‐phase shell growth pattern, first in shell length (SL), which ceases well before maturity, followed by growth in shell lip thickness (LT) into maturity. This growth pattern must be considere...

Observations from patch reef and fore-reef benthic surveys highlight that the original main structural components of living corals (Acropora spp., Siderastrea spp. and Orbicella spp.) are in decline with much of the hard bottom habitats, including coral skeletons, now dominated by fleshy macroalgae (Dictyota sp., Lobophora sp.) as well as several e...

Using information on the species composition and length-frequencies of fish caught in the spear and hook and line fisheries of Glover’s Reef Marine Reserve, Belize, we evaluated changes between 2004–2010 and 2011–2017 in single-species and ecosystem sustainability indicators. The two gears differed in species caught, and both changed species compos...

A natural refuge provides an inaccessible area that can protect populations from exploitation (Karpov et al. 1998, Tyler et al. 2009). This concept has been adopted by marine resource management to identify and protect habitats that preserve species and provide sources of replenishment to fisheries beyond no-take areas (Rowley 1994, McClanahan and...

Marine protected areas or replenishment zones have become one of the more popular tools within an ecosystem-based management approach aimed at balancing environmental health with socio-economic needs. We examined changes in populations of an ecologically representative suite of focal species, including ones important to local small-scale fisheries,...

In the face of climate change, warming oceans, and repeated mass coral bleaching, coral reef conservation is at a timely crossroads. There is a new urgency to support and strengthen a rich history of conservation partnerships and actions, while also building toward new actions to meet unparalleled global threats. The goal of this white paper is to...

In the face of climate change, warming oceans, and repeated mass coral bleaching, coral reef conservation is at a timely crossroads. There is a new urgency to support and strengthen a rich history of conservation partnerships and actions, while also building toward new actions to meet unparalleled global threats. The goal of this white paper is to...

The Belize Spawning Aggregation Working Group has been in existence since 2001. For the past fourteen years, this group of conservation NGOs, fisher organizations, academic institutions and the Belize Fisheries Department have collaborated and made significant progress in the protection and management of Belize's reef fish spawning aggregation site...

Unsustainable wildlife trade negatively impacts wild populations of traded species. Thus to assess these population impacts and manage trade, we need to find and characterize extant populations. Seahorses are one of the most heavily traded marine animals, with almost 6 million individuals exported worldwide annually. Thailand, the top exporter, is...

Despite the importance of large decapod fisheries, including many in and around coral reefs, as well as an increasing number of studies illustrating decapod top-down control of coral reef consumers (Burkepile & Hay 2007) and basal resources (Butler & Mojica 2012) the ecological importance of large decapods in maintaining tropical coral reef integri...

Empirical patterns that emerge from an examination of food webs over gradients of environmental variation can help to predict the implications of anthropogenic disturbance on ecosystems. This "dynamic food web approach" is rarely applied at the coastal margin where aquatic and terrestrial systems are coupled and human development activities are oft...

Physical features of beaches included in the study ordered by increasing beach width. See methods for details of sampling protocol. Sediment = median grain size; % wrack composition = % of dry weight (g) biomass: SG = Seagrass (Th = Thalassia testudinum, Syr = Syringodium filiforme, Hal = Halodule wrightii); MA = Macroalgae and TerrP = Terrestrial...

Mean isotopic signatures (δ13C, δ15N) used to determine diet mixture results from SIAR for beaches included in this study and ordered by increasing beach width at sites (Codes and location see Fig 3). Basal resource isotopic signatures are for dominant forms (SG = Seagrass, Th = Thalassia testudinum, Syr = Syringodium filiforme, MA = Macroalgae, Sa...

Marine Protected Areas (MPAs) are now widely used for marine conservation and fisheries management, but the effects and benefits of MPAs may depend on what uses they allow or restrict. For many conservation and fisheries management goals, no-take zones or fully protected areas can provide the greatest benefits. As part of Belize’s expansion of its...

A number of large, predatory gastropods including Chanks (Turbinellidae), Helmets (Cassidae), and Tritons (Ranellidae) are targeted by fishers supplying the trade in collectible shells, components of decorative souvenirs, and a source of food in some areas. However, the over-harvesting of these predators is considered a contributing factor in popul...

The distribution of Indo-Pacific spiny lobster populations is known to be influenced by oceanic hydrodynamics and terrestrially generated turbidity. The distinct pattern of artisanal landings for six lobster species (Panulirus homarus, P. longpipes longipes, P. ornatus, P. penicillatus, P. polyphagus, P. versicolor) on the west coast of Aceh Provin...

The crisis in the world's fisheries is well documented with many stocks being fully or overexploited. The consequences of these activities include a number of cascading effects such as alteration of trophic dynamics and simplification of complex communities. We examined seagrass communities, both macrophyte resources and mega-invertebrate abundance...

Using field surveys and stable isotope analyses of beach consumers and prey, we investigated whether the identity of dominant prey items of ghost crabs Ocypode quadrata differed across 3 barrier island beaches along the west coast of Florida, USA. Abundance of potential prey, mole crabs Emerita talpoida and coquina clams Donax variabilis, was deter...

Cassis tuberosa (King Helmet) is a large predatory gastropod found throughout the Central Western Atlantic region. We examined a relatively undisturbed population of King Helmets within a shallow bay in South Caicos, Turks and Caicos Islands, in order to develop additional knowledge regarding this potentially threatened species. The majority (74%)...

This paper describes the application of the methodology called Rapid Appraisal of Fisheries Management System (RAFMS) to assess quickly the situation in tsunami-affected coastal fisheries in Aceh Province, Indonesia. As a diagnostic tool, the RAFMS is introduced in terms of its conceptual framework and procedures. The RAFMS was used to appraise the...

In an effort to facilitate the restoration of livelihoods that reduce poverty and increase future resilience for the poor coastal communities of Aceh province, we investigated responses related to the pre-existing lobster fishery and the potential for lobster culture. Six species of spiny lobster endemic to the Indonesian archipelago (Panulirus hom...

Abstract  The tremendous loss of life and assets resulting from the 2004 tsunami dealt a devastating blow to the coastal communities of Aceh Province, Indonesia. An assessment of the fishing fleet structure pre- and post-tsunami, including associated pattern in boat aid, in 15 coastal communities was conducted and compared with data on boat relief...

Restoration has become an integral part of coastal management as a result of seagrass habitat loss. We studied restoration of the seagrass (Halodule wrightii) near Tampa Bay, Florida. Experimental plots were established in June 2002 using four planting methods: three manually planted and one mechanically transplanted by boat. Seagrass cover was rec...

Anthropogenic nutrient enrichment has resulted in significant changes in food web structure. Although such changes have been associated with the loss of diversity and ecosystem services, little empirical work has been done to study food webs of similar systems across a nutrient enrichment gradient. We examined 11 seagrass beds along a gradient of i...

Although the roles of physical disturbance and successional recovery from such disturbances in structuring natural communities are well known, recent studies have begun to uncover the potential for alternate outcomes or climax states in a number of systems. Here, we examine the distribution of tropical macrophytes at a site with heavy wave exposure...

The widespread and long-term nature of the tsunami damage in Aceh province, Indonesia has threatened the continued use of coastal and fisheries resources. This article describes the application of the Rapid Appraisal of Fisheries Management System (RAFMS) methodology and presents key findings from the participatory appraisals in 15 study sites. The...

The widespread and long-term nature of the tsunami damage in Aceh province, Indonesia has threatened the continued use of coastal and fisheries resources. This article describes the application of the Rapid Appraisal of Fisheries Management System (RAFMS) methodology and presents key findings from the participatory appraisals in 15 study sites. The...

The identification and understanding of shifts in resource availability and community structure caused by a variety of anthropogenic perturbations is essential to future rehabilitation efforts and recovery of essential ecosystem processes. We focus here on the contribution of nutrient enrichment to the overgrazing of macrophyte-dominated systems, w...

We illustrate the skewed spatial and temporal patterns of fishing effort and the associated non-compliance with regulations within the spiny lobster fishery based in South Caicos, Turks and Caicos Islands. The size, maturity, and breeding status of lobsters caught by divers (4321 from 179 boat trips) from five fishing grounds over the 8-month fishi...

Spiny lobster populations within the Bocas del Toro archipelago appear to be overexploited. Extensive visual surveys over a wide area of reef habitat down to 20 m in depth indicate mean lobster abundance, sizes, and percent maturity levels for both Panulirus argus and P. guttatus below other areas in the region. The almost complete absence of egg-b...

Extensive visual surveys for the economically and ecologically significant queen conch (Strombus gigas) and milk conch (Strombus costatus) were conducted within the Bocas del Toro archipelago. Overall population densities are among the lowest recorded in the region (S. gigas 1.43 conch ha-1; S. costatus 1.27 conch ha-1), and are likely the result o...

Abstract This study provides a first evaluation of the biological impact of a marine fishery reserve on the stock of queen conch (Strombus gigas) in the Turks and Caicos Islands. The density and the shell length of the population living in the reserve are compared with those of the individuals living in the surrounding fished areas. The results sho...

The movement of organisms and dispersal of propagules is fundamental to the maintenance of populations over time. However, the existence of barriers, created through the spatial configuration of habitats, may significantly affect dispersal patterns and thus influence community dynamics and resource sustainability. Within marine environments unstruc...

In this paper we analyze the fishing effort allocation of fishermen in the artisanal fisheries of the Turks and Caicos Islands (British West Indies).These fishermen use a free-diving technique to simultaneously exploit the local stocks of queen conch and spiny lobster. Using an integrated framework combining a set of analytical tools within a multi-dis...

Queen conch (Strombus gigas) is the second most valuable (price per unit weight) species harvested by fishers in Antigua and Barbuda. A visual abundance survey was undertaken to assess the status of the exploited stocks. Belt transect methodology was employed with the assistance of underwater scooters. All conch found within a transect were placed...

In this paper we analyze the fishing effort allocation of fishermen in the artisanal fisheries of the Turks and Caicos Islands (British West Indies). These fishermen use a free-diving technique to simultaneously exploit the local stocks of queen conch and spiny lobster. Using an integrated framework combining a set of analytical tools within a mult...

The powerful effect of MPAs in altering population densities and size/age structure is thus well illustrated with the protection of adult spawning stock of queen conch within the EHLCR, South Caicos, Turks and Caicos Islands. However, the other benefits of MPAs in improving conch fishery productivity in the TCI, emigration of stock into surrounding...

A study was conducted to gather baseline data on the present condition of the spiny lobster stocks within the Cayos Cochinos Archipielago using direct visual assessment techniques. Data collected would allow the initial estimate of total abundance and density of lobster species, as well as of the distribution of populations by habitat type and wate...

A visual preliminary assessment of the Strombus gigas population in the area of the Cayos Cochinos Biological Reserve was conducted by SCUBA divers swimming transects. Additional data on size/age structure, morphometries (shell length, shell width, shell lip thickness, and total weight), habitat, and reproductive activity were also collected. Size...

Although Jamaica had not traditionally been known for conch exploitation, large exports of conch have been coming from the island since 1991. The majority (approx. 95%) of this exploitation has come from Pedro Bank (Figure 1) off the islands’ southern coast. As a result, Jamaica has been considered the top producer of conch in the Caribbean since t...

This report has been prepared to provide regional fisheries biologists and managers with up-to-date information on the queen conch. The information will assist in decisions regarding management options and overall strategies for the sustainable use of queen conch resources. The report has been divided into sections on life history and ecology, fish...