English: Ecological connections and functions enhanced by surface slick nurseries
(1) Larval and juvenile stages of fishes from many ocean habitats aggregate in slicks in order to capitalize on dense concentrations of prey (2, phytoplankton, 3, zooplankton, 4, larval invertebrates, 5, eggs, and 6, insects). The increased predator–prey overlap in slicks increases energy flow that propagates up the food-web (dotted blue lines show trophic links), enhancing energy available to higher trophic level predators (icons outlined in blue) including humans. More than 100 species of fishes develop and grow in surface slick nurseries before transitioning to adults (solid white lines radiating outward) in Coral Reefs (7–12), Epipelagic (13–15), and Deep-water (16–17) ocean habitats. As adults these taxa (icons outlined in white) play important ecological functions and provide fisheries resources to local human populations. For example, coastal schooling fishes (7, mackerel scad) are important food and bait fish for humans. Planktivorous fish (8, some damselfishes and triggerfishes) transfer energy from zooplankton up to reef predators47 like jacks (9), which provide top-down control of reefs48 and are important targets for shoreline recreational fisherfolk. Grazers (10, chubs) help keep coral reefs from being overgrown by macroalgae. Cryptobenthic fishes such as blennies (11) and benthic macrocrustaceans (12, shrimp, stomatopods, crabs) comprise most of the consumed biomass on reefs. In the pelagic ocean, flyingfishes (13) channel energy and nutrients from zooplankton to pelagic predators such as mahi-mahi (14) and billfish (15), both of which utilize slicks as nursery habitat. Larvae of mesopelagic fishes like lanternfish (16) and bathydemersal tripod fishes (17) utilize these surface hotspots before descending to deep-water adult habitat. Surface slicks are clearly the focal point for numerous trophic and larval connections that are foundational for marine ecosystem function. For clarity, the diagram only illustrates several key examples and does not represent the full breadth of ecological connections enhanced by surface slicks.