Empirical measurements of ammonium excretion in kelp forest fishes: Effects of body size, taxonomy and trophic guild

Fishes and other consumers excrete metabolic waste products, including dissolved nutrients rich in nitrogen, which is an essential nutrient for primary production. Relatively little is known about the magnitude and variability of nutrients excreted by fishes in kelp forest ecosystems and whether consumer-derived nutrients are important for supporting kelp productivity. In this study, the supply of ammonium (NH4+) excreted by the dominant fishes (30 species representing ~85% of total fish biomass) was investigated on nearshore rocky reefs in California. Using rapid field incubations, the amount of excreted dissolved ammonium was measured as a function of body size (n = 460 individuals), and predictive models were developed relating mass to excretion rates at the family level. Mass-specific excretion rates ranged from 0.08 – 3.45 µmol·g-1·hr-1, and per capita ammonium excretion rates ranged from 5.9 – 2765 µmol·individual·hr-1. Ammonium excretion scaled with fish body mass to the ¾ power,..., To quantify rates of ammonium excretion for the dominant fish species inhabiting nearshore rocky reefs and kelp beds in central and southern California, we utilized established techniques in the field for rapid empirical estimation of consumer-derived nutrient excretion in aquatic systems. We selected a subset of 30 species, from 13 families, to represent the dominant fish species comprising California kelp forests. The selected species represented ~85% of total fish biomass, based on estimates of density and biomass from extensive underwater visual surveys conducted by the Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO) in central and southern California. Each fish species was assigned to one of five trophic guilds based on discrete, fixed trophic delineations (herbivore/omnivore, planktivore, micro-carnivore, macro-carnivore, and piscivore) as established in the literature. Herbivores/omnivores consist of species that consume a relatively large proportion of algae ..., , # Empirical measurements of ammonium excretion in kelp forest fishes: Effects of body size, taxonomy and trophic guild

[https://doi.org/10.5061/dryad.0p2ngf29v](https://doi.org/10.5061/dryad.0p2ngf29v)

## Description of the data and file structure

The data consists of experimental incubations of kelp forest fish in California, USA across 30 species and a range of body sizes, measuring ammonium excretion rates.

### Files and variables

#### File: Shrestha\_kelp\_forest\_fish\_ammonium\_excretion\_all\_fish.xlsx

**Description:** This data set contains measurements of ammonium excretion rates of kelp forest fishes from central and southern California. This data set contains information for every individual and species incubated to measure ammonium excretion

##### Variables

* Fish_ID - Specific ID number for each fish in the data set
* Region - Region in California where fish were collected (central or southern California)
* Collection location-specific site where the fish were colle...