Charles Jacoby Linda Walters Shirley Baker Karen Blyler Florida Sea Grant College Program • http://www.flseagrant.org • SGEB 60 1 Acknowledgments Funding and support We thank Mike Spranger for his encouragement This publication was supported by the National throughout the development of this primer. Sea Grant College Program of the U.S. Steve Kearl and Dorothy Zimmerman provided Department of Commerce’s National Oceanic valuable editorial input. and Atmospheric Administration (NOAA) under NOAA Grant No. NA16RG-2195. The views expressed are those of the authors and do not The authors necessarily reflect the views of these organizations. Charles Jacoby is an Assistant Professor and Extension Specialist in the Department of The Florida Sea Grant College Program, the Fisheries and Aquatic Sciences at the University Southeast Regional Aquatic Nuisance Species of Florida in Gainesville, Florida. (ANS) Education and Outreach Network, a partnership between the Sea Grant College Shirley Baker is an Assistant Professor in the Programs in Alabama, Florida, Louisiana, and Department of Fisheries and Aquatic Sciences at Mississippi, UF/IFAS Extension and the the University of Florida in Gainesville, Florida. University of Central Florida provided support for the development of this document. Linda Walters is an Assistant Professor in the Department of Biology at the University of Additional funds to support publication of this Central Florida in Orlando, Florida. document were provided by the Tampa Bay Estuary Program. Karen Blyler is the Coordinator of Education and Training in Aquatic and Environmental Science for the Florida 4-H Youth Development Program at the University of Florida in Gainesville, Florida. Photo credits Cover, upper left: Phyllorhiza punctata, an Indo-Pacific jellyfish now found in large numbers around the Gulf of Mexico. (Photo courtesy Dauphin Island Sea Lab) Cover, center left: Perna viridis, an Indo-Pacific mussel that became established in Tampa Bay and has spread around Florida and into Georgia. (Photo courtesy U.S. Geological Survey) Cover, lower left: Pterois volitans, an Indo-Pacific fish often kept in saltwater aquaria that is now found along the east coast of the United States. (Photo courtesy J.E. Randall) Cover, bottom half: Aerial photograph of an explosion of the Australian spotted jellyfish (Phyllorhiza punctata) in the Gulf of Mexico. (Photo courtesy Dauphin Island Sea Lab) Page 1, upper right: Pterois volitans, an Indo-Pacific fish often kept in saltwater aquaria, is now found along the east coast of the United States. (Photo courtesy J.E. Randall) 2 What are invasive species? nvasive species have looking at the history of species I entered an area that is introductions, the harm caused by not part of their natural invasive species, how invasive range. They represent one type of species are introduced and become alien, non-native, nonindigenous invasive, and how we can manage or introduced species. In contrast, our own actions and activities to native or indigenous species occur help solve the problem. in an area naturally. Invasive species that are native or intro- How long have invasive duced differ from beneficial native species been around? and non-invasive species because they can or do cause harm to the People began introducing species as economy, the environment or soon as they could travel. For human health. Typically, invasions example, beginning around 1500, involve the spread of an introduced Europeans transported Old World species. Natural vectors, such as species to their new settlements in storms, or vectors associated with the Western Hemisphere and human activities may cause elsewhere. The manifests from Columbus’ second and subsequent People apply a confusing introductions and subsequent and muddled collection of invasions by moving species along voyages indicate deliberate trans- words to invasive species. pathways. Human introductions port of species regarded as poten- may be intentional or uninten- tial crops and livestock. A glossary found on pages tional, and both types of introduc- Humans continue to disperse 14 and 15 provides species, and the worldwide increase tions can cause bioinvasions. We definitions for key terms in plant, animal, and microbial can add a political bent to the used in this publication. discussion by applying the term introductions roughly tracks exotic to species that have entered the increase in human a new country and using the term transport and commerce. In transplanted for species moved to particular, the meteoric new areas within the same country. growth of global commerce Whatever definitions we choose, in the past 200 to 500 years we should all be concerned about has produced numerous invasive species and the harm they opportunities for biotic cause. First, we want to avoid invasions. During this time harmful consequences from span, the scope, frequency introductions. Second, our actions and impact of people’s or activities can spread invasive deliberate and accidental species, so we are responsible for movements of organisms managing both introductions and undoubtedly dwarf the any consequences. Managing effects of natural forces invasive species will not simply be during any 500-year period a matter of banning all introduc- in the earth’s history. For tions because all of us benefit from example, introductions to Figure 1. Rate of new invasions by marine invertebrates and seaweeds in the U.S. coastal some introductions and many coastal habitats in the United States have increased zone from 1790 to 1999 (374 total invasions). introductions are accidental or Source: Ruiz et al., 2000; Carlton, 2001. unintentional. We can improve our over 100-fold in the last management of invasive species by 200 years (Figure 1). A PRIMER ON INVASIVE SPECIES IN COASTAL AND MARINE WATERS 1 Box 1. Throughout history, we have What harm do invasive Deliberate and accidental introductions of accidentally and deliberately intro- species cause? invasive species. duced numerous species. Our Introduced species typically do O deliberate introduction of few, if any, invasive tendency to accidentally or deliber- microorganisms, although we introduced ately introduce invasive species not survive and reproduce; there- yeasts for fermentation and mutualists, such varies among types of organisms fore, they seldom establish themselves as the symbiotic, mycorrhizal fungi found in (Box 1). The number of deliberately and become invasive (Figure 2). plant roots introduced species that become Introductions can be viewed as an O deliberate introduction of some insects that invasive emphasizes the fact that not ecological parallel to Russian have caused adverse consequences, such as all pests arrive unheralded and roulette. We ‘load bullets into a bumblebees in New Zealand, but the majority gun and spin its cylinder’ by of invasive insects have probably been inconspicuously. Many of our worst introduced accidentally problems are the product of our moving species beyond their own deliberate but flawed plans. natural ranges. Then, we ‘pull the O deliberate introduction of a few marine trigger’ by introducing species into invertebrates, such as the Pacific oyster imported from Japan to Washington state, but a growing number of invaders, such as the zebra mussel, have arrived accidentally as contaminants in ballast water and through other vectors O deliberately introduced most invasive vertebrates, principally fish, mammals and birds, although some of the worst vertebrate invaders have been spread accidentally, such as rats, brown tree snakes and sea lampreys O deliberately introduced many, if not most, plant invaders, including water hyacinth, melaleuca trees, salt cedar and other serious pests, although some invasive plants have been accidentally introduced as contami- nants among crop seeds and other cargo Figure 2. Steps in becoming an invasive species. 2 A PRIMER ON INVASIVE SPECIES IN COASTAL AND MARINE WATERS new ranges and take our chances on efficiently. For example, Box 2. whether they cause harm by estab- invasive plants typically out Examples of how invasive species harm lishing and spreading. As in any compete natives by shading populations. game of chance, the outcome of a them or using scarce water. O Asian chestnut blight fungus arrived in New York City given round is uncertain. We may When a species interferes on nursery stock early in the 20th century and, within introduce numerous species or one with or harms another in the a few decades, the blight had spread and destroyed species numerous times and suffer no competition for resources, almost all the American chestnuts that had once dominated forests in the eastern United States significant consequences, or we may ecologists call it interference (disease) introduce a single species once and competition. Invasive species generate immense harm. In general, clearly demonstrate this tactic. O predatory Nile perch introduced into Africa’s Lake Victoria has eliminated or gravely threatens more species cause harm by affecting plant For example, many invasive than 200 of the 300 to 500 native species of small, and animal populations or commu- animals exhibit aggressive cichlid fishes (predation) nities, ecosystems and ecosystem behavior that drives native O feral and domestic cats introduced to every part of services, or our economy. animals out of their natural the world have depleted breeding populations of ranges, and invasive plants may seabirds and endemic land birds on oceanic islands Effects on populations produce