Project Information

Spatio-temporal movement patterns and FAD association of pelagic sharks around the main Hawaiian Islands

Fish aggregating devices (FADs) are a critical fisheries enhancement tool for tropical commercial (i.e. purse seine fisheries) and small-scale fisheries throughout the world. Around the main Hawaiian Islands of Maui, Hawaii, Oahu, and Kauai the State has established a FAD Program with the purpose of increasing fishing opportunities by attracting schools of tuna and other important pelagic fishes such as; dolphinfish, wahoo, and billfish. Pelagic sharks are also often encountered by fishers around the FADs, where they forage on fish schools. This means sharks frequently compete with fishers for catch. The need to understand Fish Aggregation Device (FAD) associative behavior to devise mitigation strategies for high seas and local fisheries impacting endangered shark populations is of paramount importance, especially around the main Hawaiian Islands. By deploying acoustic receivers on the pre-existing network of FADs around the main Hawaiian Islands, this study uses acoustic telemetry to elucidate spatial and temporal hotspots, including potential areas of biological significance for endangered shark populations around Hawaii. If Hawaii is an important habitat for mating or partuition it is critical to population growth that efforts to reduce mortality in the recreational and commercial fisheries are initiated. These data may also enhance Hawaii fisheries by elucidating times and areas of residency when fishers can improve their practices to avoid certain areas and reduce costs related to shark depredation.

Contact:

• Melanie Hutchinson, NOAA Pacific Islands Fisheries Science Center, Principal Investigator, melanie.hutchinson@noaa.gov

• Molly Scott, NOAA Pacific Islands Fisheries Science Center, Principal Investigator, molly.scott@noaa.gov

Citations: Stahl J, Tucker J, Rassel L, Hawn L. 2024. Data collectable using electronic monitoring systems compared to at-sea observers in the Hawaiʻi Longline Fisheries.

Molokini Fish Tracking Array

Humans alter ecosystems through both consumptive and non-consumptive effects. Consumptive effects occur through hunting, fishing and collecting, while non-consumptive effects occur due to the responses of wildlife to human presence. While marine conservation efforts have focused on reducing consumptive effects, managing human presence is also necessary to maintain and restore healthy ecosystems. Area closures and the tourism freeze related to the COVID-19 pandemic provided a unique natural experiment to measure the effects of decreased tourism on fish behavior in a high use no-take marine protected area (MPA) in Hawai`i. We found that when tourism shut down due to COVID restrictions in 2020, fish biomass increased and predatory species increased usage of shallow habitats, where tourists typically concentrate. When tourism resumed, fish biomass and habitat use returned to pre-pandemic levels. These displacement effects change fish community composition and biomass, which could affect key processes such as spawning, foraging and resting, and have knock-on effects that compromise ecosystem function and resilience. Managing non-consumptive uses, especially in heavily-visited MPAs, should be considered for sustainability of these ecosystems.

Contact:

• Kevin Weng, Virginia Institute of Marine Science - William & Mary, Principal Investigator, kevincmweng@gmail.com

Citations:

Weng KC, Friedlander AM, Gajdzik L, Goodell W, Sparks RT. 2023. Decreased tourism during the COVID-19 pandemic positively affects reef fish in a high use marine protected area. PLoS ONE 18(4): e0283683.

Critical habitat, movement ecology and population connectivity of scalloped hammerhead sharks (Sphyrna lewini) in the central Pacific Ocean.

Scalloped hammerhead sharks are considered globally threatened or endangered across their range, but conservation and management strategies are ham-strung by data deficiency. This largely stems from their enigmatic nature and tendency toward sexual segregation. In order to afford meaningful and effective conservation and management measures to the species, these glaring gaps in our knowledge need to be addressed. The study primarily aims to address data deficiencies that have resulted in the (arguable) mis-classification of the central Pacific distinct population segment of scalloped Hammerhead sharks, and to significantly broaden the effort to elucidate critical habitat and movement ecology, while re-examining population connectivity of scalloped hammerhead sharks of the central Pacific Ocean.

Contact:

• James Anderson, CSULB Sharklab & HIMB Pelagic Fish Research Lab, principal investigator, ja25@hawaii.edu

Contact:

Anderson, J. 2020. Critical habitat,movement ecology and population connectivity of scalloped hammerhead sharks (Sphyrna lewini) in the central Pacific Ocean.

Missing Project Description

Contact:

• Carl Meyer, HIMB Shark Lab, Principal Investigator, meyersl@hawaii.edu

• Kim Holland, HIMB Shark Lab, Principal Investigator, kholland@hawaii.edu

Citations:

Papastamatiou Yannis P., Itano David G., Dale Jonathan J., Meyer Carl G., Holland Kim N. 2010. Site fidelity and movements of sharks associated with ocean-farming cages in Hawaii. Marine and Freshwater Research 61, 1366-1375.

Human-Wildlife Conflict Between Sharks and Tuna Fishers at Fish Aggregating Devices in Niue

This study investigates the human-wildlife conflict between sharks and tuna fishers at Fish Aggregating Devices (FADs) in Niue, using acoustic telemetry to track the movements of both predator and prey species. By tagging Silky sharks (Carcharhinus falciformis), Oceanic whitetip sharks (Carcharhinus longimanus), Mako sharks (Isurus oxyrinchus), Grey Reef sharks (Carcharhinus amblyrhynchos), and Yellowfin tuna (Thunnus albacares), the research aims to identify patterns in residency, spatial distribution, and usage of FADs. The data gathered will be used to inform potential mitigation measures to limit shark depredation on tuna catches, helping reduce conflicts between fishers and wildlife and promote sustainable fishing practices in Niue's tuna fisheries

Contact:

• Jess Cramp, Sharks Pacific, Principal Investigator, jess@sharkspacific.org

• Vinay Udyawer, Sharks Pacific, Principal Investigator, vinay@sharkspacific.org

Citations:

Cramp, J., Udyawer. V. 2024. Human-Wildlife Conflict Between Sharks and Tuna Fishers at Fish Aggregating Devices in Niue

O'io (Albula glossodonta) space use and residency

This project represents a preliminary investigation into space use patterns of o'io on a Hawaiian reef flat.

Contact:

• Brad Smith, Brigham Young University - Hawaii, Principal Investigator, brad.smith@byuh.edu

Citations:

Smith, B., & Dance, M., TinHan, T., Rooker, J. 2022. O'io space use and residency

Movement and habitat use of elasmobranchs around Aitutaki, Cook Islands

This study investigates the movement patterns and habitat use of elasmobranchs within and around the lagoons of Aitutaki, Cook Islands.

Contact:

Contact:

• Jess Cramp, Sharks Pacific, Principal Investigator, jess@sharkspacific.org

• Vinay Udyawer, Sharks Pacific, Principal Investigator, vinay@sharkspacific.org

Website:

https://sharkspacific.org

Investigating ontogenetic shifts in the spatial ecology of sicklefin lemon (Negaprion acutidens) and blacktip reef sharks (Carcharhinus melanopterus) and their ecological impact in a minimally disturbed nursery habitat

Coastal nursery areas are widely considered to be critical habitat for sharks and are of increasing importance given recent declines of many populations across the globe. These essential areas provide habitats for sharks to feed, reproduce, and/or refuge to grow to maturity. Understanding how sharks utilize these habitats, both spatially and temporally, is thus critical for developing species-specific management plans and conservation measures. Previous research has focused on how multiple shark species may inhabit the same nursery, highlighting how habitats may be partitioned in time and space as well as investigating trophic interactions. Less attention, however, has been given to how these dynamics may change in relation to the size/age within a single species. Such ontogenetic shifts in how nursery areas are used could have population level consequences as a result of increased competition, which is likely to have the greatest impact on younger individuals whose survival rates strongly influences population growth rates, particularly for exploited populations. Of the limited studies that have examined differences in movement patterns between age classes, nearly all have been conducted within stressed environments that have experienced varying degrees of fishing pressure and/or habitat degradation. Accordingly, there remains a need to establish a baseline for how sharks utilize these key habitats in a relatively undisturbed ecosystem. Here we propose to study the spatial ecology of two large marine predators, the sicklefin lemon shark (Negaprion acutidens) and blacktip reef sharks (Carcharhinus melanopterus), and how these movement patterns may vary in relation to age/size within a relatively undisturbed nursery: Tetiaroa, French Polynesia. Using a combination of passive acoustic and underwater video data, we will compare how space use within the nursery differs between individuals, as well as across different age classes. Specific metrics to compare between individuals and across different age classes: Residency time, home range size, core use areas, natal homing, time before dispersal from natal site, social networks, influences of environmental factors on these metrics, and changes in species richness and relative abundances of reef fishes.

Contact:

• Aaron Wirsing, University of Washington, Principal Investigator, wirsinga@uw.edu

Citations:

Wirsing, A., Gastrich, K., Farabaugh, N.F., Clementi, G., Kilfoil, J., Caselle, J., Heithaus, M., Planes, S., Clua, E. 2024. Investigating ontogenetic shifts in the spatial ecology of sicklefin lemon (Negaprion acutidens) and blacktip reef sharks (Carcharhinus melanopterus) and their ecological impact in a minimally disturbed nursery habitat.

Acoustic monitoring of sub-adult green turtle (Chelonia mydas) populations in Tetiaroa lagoon

Tags, whether satellite or acoustic, are widely used techniques for addressing ecological and biological questions related to the movement of individuals in the ocean. The movement and distribution of sub-adult green turtles (Chelonia mydas) in the lagoon of Tetiaroa Atoll (French Polynesia) have been studied using acoustic tags since July 2024. Ten turtles, ranging from 47.4 to 63.7 cm in curved carapace length (CCL), have already been fitted with Vemco acoustic tags. An additional ten tags are scheduled to be deployed in the coming months. Fifteen receivers have been installed inside Tetiaroa Lagoon, in both deep and shallow waters, to cover the largest possible surface area of the lagoon. Data from the receivers are collected every six months.

Contact:

• Jade Gouin, Te Mana O Te Moana, Principal Investigator, tortues@temanaotemoana.org

Citations:

Anaa Atoll French Polynesia Bonefish

Teleost fish that form predictable spawning aggregations and undertake reproductive migrations can be particularly vulnerable to overexploitation. To support community-based management of an artisanal fishery that targets bonefish (Albula glossodonta) spawning aggregations, we used a combination of acoustic telemetry, biological sampling, and remote imagery to reveal the spatiotemporal spawning migrations of bonefish on Anaa Atoll in the Tuamotu Archipelago, French Polynesia. The spawning migrations of bonefish tracked with acoustic telemetry were restricted to the northern section of the atoll, with 99.6% of all detections at offshore spawning habitats occurring on fixed acoustic receivers adjacent to the atoll’s artisanal fish trap complex. Male bonefish undertook spawning migrations more frequently than females and these spawning migrations were common during the Austral winter and fall. The movements of bonefish spawning aggregations coincided with the lunar cycle, as a network analysis revealed an increase in network size and the diversity of habitat use within our acoustic array throughout the duration of the waning moon. Our results highlighted the need for the management of the artisanal trap fishery to prevent the overharvest of bonefish during their peak spawning periods. In response to the spatiotemporal management recommendations derived from this research, the local government established an Educational Managed Marine Area that includes the atoll’s bonefish spawning migratory corridor adjacent to Tukuhora village and a Rahui (i.e., seasonal closure) to improve the sustainability of the fishery.

Contact:

• Alexander Filous, The Nature Conservancy, Principal Investigator, afilous@hawaii.edu

• Alan M. Friedlander, PS-NGS, Principal Investigator, friedlan@hawaii.edu

• Andy Danylchuk, University of Massachusetts, Principal Investigator, adanylch@umass.edu

Citations:

Palau FADs and EcoBuoy

N/A description

Contact:

• Alexander Filous, The Nature Conservancy, Principal Investigator, afilous@hawaii.edu

• Andy Danylchuk, University of Massachusetts, Principal Investigator, adanylch@umass.edu

• Natalie Arnoldi, Stanford University, Principal Investigator, narnoldi@stanford.edu

Citations:

Palau FADs and Tuna

N/A Description

Contacts:

• Alexander Filous, The Nature Conservancy, Principal Investigator, afilous@hawaii.edu

• Robert Lennox, Dalhousie University, Principal Investigator, robert.lennox@dal.ca

• Yimnang Golbuu, The Nature Conservancy, Principal Investigator, yimnang.golbuu@tnc.org

Citations:

Filous, A., Alan M Friedlander AM., Toribiong M, Lennox, R, Mereb, G, Golbuu, Y. 2025. The movements of yellowfin tuna, blue marlin, and sailfish within the Palau National Marine Sanctuary and the western Pacific Ocean, ICES Journal of Marine Science, Volume 79, Issue 2, March 2022, Pages 445–456

Molokini and Maui Nui Hawaii

N/A Description

Contact:

• Alexander Filous, The Nature Conservancy, Principal Investigator, afilous@hawaii.edu

• Alan M. Friedlander, Polar Seas - National Geographic Society, Principal Investigator, friedlan@hawaii.edu

• Russell T. Sparks, Hawaii Division of Aquatic Resources, Principal Investigator, russell.t.sparks@hawaii.gov

Citations:

Final Report on the Movement of Predatory Reef Fishes in the Molokini Marine Life Conservation District. 2016.

Filous, A., Friedlander, AM., Koike, H. Lammers, M., Wong, A., Stone, K., Sparks, RT. 2017. Displacement effects of heavy human use on coral reef predators within the Molokini Marine Life Conservation District, Marine Pollution Bulletin, Volume 121, Issues 1–2,2017, Pages 274-281, ISSN 0025-326X