Defense Date
4-22-2022
Document Type
Thesis
Degree Type
Master of Science
Degree Name
Marine Science
First Advisor
Tracey Sutton, Ph.D.
Second Advisor
Tamara Frank, Ph.D.
Third Advisor
Jose Lopez, Ph.D.
Keywords
Ceratioidei, anglerfishes, mesopelagic, bathypelagic, ecology, assemblage, Gulf of Mexico, vertical distribution, faunal composition.
Abstract
The bathypelagic zone, despite being the largest cumulative ecosystem on the planet, represents the largest data gap in biological oceanography. In a deep environment with no solar light and pressures so high that survival is impossible for most marine organisms, some species have been able to adapt and overcome these challenges to radiate into diverse and successful taxa. Among the most notable of these successful taxa are the deep-sea anglerfishes (Lophiiformes: Ceratioidei). Ceratioid anglerfishes possess unique adaptations such as a symbiotic bioluminescent lure (females) and extreme dwarfism (males) that make them a particularly interesting group to study. Despite this research attractiveness, low sample sizes in ichthyological questions preclude detailed characterizations of fundamental assemblage properties, such as faunal composition, sex ratios, and vertical distributions in specific water bodies; i.e., most of what we know is compiled from sparse data across all oceans.
Ceratioids were collected in the Gulf of Mexico (GoM) as a part of an extensive pelagic survey following the Deepwater Horizon oil spill. Using high-speed rope trawls and a multiple opening and closing net system, ceratioids were collected day and night throughout the northern GoM. The faunal composition of females, males, and larvae were analyzed separately by life stage/sex and by family to gain insight into assemblage structure and vertical distribution.
A total of 1726 ceratioids were collected, representing all 11 families in the suborder. The assemblage was dominated numerically by females of the family Ceratiidae, in particular the species Cryptopsaras couesii. Males and larval numbers were dominated by the family Linophrynidae. The type of net used affected the taxon and size of specimens captured. Four patterns of vertical distributions were identified: 1) primarily epipelagic distribution with a rapid descent to great depth; 2) primarily mesopelagic residence; 3) a wide, “spanner” vertical distribution independent of solar cycle; and, 4) a primarily bathypelagic distribution. Larvae, particularly Linophrynidae larvae, best typified Pattern 1, the family Ceratiidae typified Pattern 2, the linophrynid species Haplophryne mollis typified Pattern 3, and males of many taxa typified Pattern 4. Vertical distribution patterns were not strictly related to taxon, sex, or life stage; for example, females within the same family (e.g., Linophrynidae) often displayed different patterns. This study demonstrates that ceratioid anglerfishes are not only among the most successful fish taxa of the bathypelagic zone, they also occupy one of the largest depth ranges among all taxa.
NSUWorks Citation
Kimberly S. Schmutz. 2022. Assemblage Composition and Vertical Distributions of Deep-Sea Anglerfishes (Suborder: Ceratioidei) of the Northern Gulf of Mexico. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, . (79)
https://nsuworks.nova.edu/hcas_etd_all/79.